Crispy Meringue Oven S'mores

These crispy meringue oven s'mores are the best no fire, no mess, make-ahead alternative to campfire s'mores. Instead of a gooey marshmallow center these crispy meringue s'mores are made in the oven and have a crispy filling made of sweet Swiss meringue. They're so easy to assemble and so much fun to make! ***Make sure you read the FAQ and notes for a successful Swiss meringue!***

These crispy meringue s'mores bars started as a pastry school project (see them here!). We had learned all the different types of meringue (French, Italian, and Swiss) and our morning assignment was just... have fun with meringue!

For my project, I drizzled chocolate ganache over graham crackers, piped on some ganache kisses, then covered them with a swirl of Swiss meringue, torched it for maximum s'mores vibe and popped them in a 200F degree oven for 4 hours to dry out the meringue and make it crispy. They were SO good, but awkwardly shaped and kind of hard to eat. But we all agreed I had a kernel of a good idea there. I just needed to refine it.

Notes from Recipe Testing

I've tested these oven baked s'mores bars so many times over the past few weeks — different types of meringue, different piping tips, different sizes of graham cracker, etc.

I started with a chocolate ganache coating for the crackers, but quickly realized s'mores are best enjoyed with a classic: Hershey's Milk Chocolate Bars. How's that for refining? So simple. So easy!

Each graham cracker sandwich gets two rectangles of Hershey's Milk Chocolate and a swirl of Swiss meringue. Even though we're making these crispy s'mores in the oven, the chocolate rectangles melt just slightly in the low heat without losing their shape, and firm back up as they cool. I love how they look melted even when they're not hot anymore.

The Swiss meringue is flavored with vanilla to really bring out the marshmallow vibes and it's just so good. Super crispy and crunchy, with that great chocolate-vanilla-graham cracker flavor combo you expect from campfire s'mores.

Jimmy brought several test batches in to the teacher's lounge and said that of all the desserts I've sent in with him these were by far the most popular amongst the other teachers. So basically: When you show up with crispy meringue s'mores, expect to be the most popular person at the party/break room/picnic/bake sale.

How to Make Swiss Meringue (Stella Parks' method)

I tested a few different methods of making Swiss meringue for these crispy meringue s'mores. There's the method I learned in pastry school, aka the double boiler with a whisk situation. I even tried Dominique Ansel's method which uses powdered sugar. The Swiss meringue method I finally settled on, the one that works best for me and that gave the most reliable results, is Stella Parks' method from Serious Eats.

To make Swiss meringue you whisk egg whites and sugar together over a double boiler to gradually raise the temperature of the egg whites so that they coagulate (cook) without turning into scrambled eggs. Then you whip the egg and sugar mixture to force air into it. The sugar (along with cream of tartar) helps stabilize the egg whites, creating a sweet and fluffy network of trapped air. Yum!

What makes Stella's method different: Stella's method has you use a silicone spatula (instead of a whisk) to stir the egg whites and sugar over the double boiler. Her method also uses a unique double boiler set up: A crinkled ring of aluminum foil inside a wide, shallow skillet. Your bowl sits on top of the aluminum foil ring (she calls it a "booster seat") to keep it out of the water, and the wide-shallow skillet provides a gentler, more even heat so the eggs don't over cook.

Once the egg white and sugar mixture reaches 175F, transfer it into the bowl of a stand mixer with a whisk and whip it at high speed for about 5-6 minutes until it reaches stiff peaks (see FAQ below for what to look for!).

Quick Tips for Perfect Swiss Meringue

• It is SUPER IMPORTANT that you don't have ANY fat or grease in your mixing bowl(s) or on the whisk or your hands when you're making meringue. As much as it pains me to admit it, in the case of meringue, fat is bad. I'm going to repeat this a few times throughout this post but it really is that IMPORTANT. Egg yolks are primarily made of fat, so when you're separating your egg yolks from the whites make sure you have a clean separation. If an egg yolk bursts and even the tiniest speck of fat gets into the bowl, you won't be able to get stiff peaks. Wipe down the whisk and both mixing bowls with a bit of vinegar on a paper towel to remove any trace amounts of fat and help stabilize the meringue before you start.
• Moisture is the enemy of meringue and will prevent it from setting up properly. If you have an air conditioner, run it. If your hands are damp, dry them. Make sure your mixing bowls and kitchen tools are dry before you start working. And make sure you have a dry, airtight container to transfer the s'mores to once they're cool.
• Make sure the ends of the aluminum foil "booster seat" ring are squished together. The first time I used Stella's Swiss meringue method I didn't squeeze the two ends of the ring together and the weight of the bowl slowly pushed the booster seat open.
• This meringue recipe makes EXACTLY enough for 24 crispy meringue s'mores. If you'd rather have a little more to work with, you can do 3 egg whites and 6 oz granulated sugar OR 4 egg whites and 8 oz granulated sugar.
• Use any extra meringue to make crispy meringue cookies. Pipe leftover meringue into spirals, stars, or any designs you want on a parchment or silicone mat lined sheet pan and pop them in the oven with the s'mores. They'll dry out into crispy meringue cookies or decorations that you can use on top of cakes and pies, or just to snack on for fun.
• Don't worry if your meringue doesn't come out perfectly. Even in batches where my crispy Swiss meringue came out less than perfect (e.g. it ended up oozing out the sides of the s'mores as it dried) the s'mores still tasted great.

ingredient notes

You need just a few basic ingredients to make these crispy meringue s'mores. You can feel free to get creative with some of them, but there are a few must-haves, especially for the meringue.

Equipment Notes

• Aluminum foil: To create the booster seat in the skillet for your double boiler situation. Don't crinkle the foil too tightly — you want it to give just enough stability and height to keep the bowl elevated out of the water. Alternately, you could use a metal steamer shelf insert for an Instant Pot if you have one (something like this).
• Instant read thermometer: This is super important for making sure the egg and sugar mixer reaches the right temperature (175F) before you start whipping.
• Egg separator (optional): If you're unsure of your egg separating skills, there's no shame in using an egg separator like this. If you get even the tiniest speck of yolk in your egg whites your meringue won't whip up, so clean egg separation is very important!
• Silicone spatula: To stir the egg whites and sugar together over the double boiler a silicone spatula is the best tool for scraping the bottom of the bowl to make sure no egg whites are cooking and sticking to the bottom.
• Kitchen scale: Meringue is all about ratios! One large egg white is 1 oz (~30 grams). You need a 1:2 ratio of eggs to sugar by weight.
• Wide, shallow skillet with high sides: It needs to be deep enough for you to fill about an inch of water at a rolling boil with room to spare. You don't want the bowl to "plug" the top of the pan.
• Heat-safe glass or metal bowl: No rubber bottomed or plastic mixing bowls allowed. They won't conduct heat well over a double boiler and you risk melting or damaging the bottoms of the bowls. Metal or glass only.
• Mixer with whisk attachment: Swiss meringue is not easy or practical to whisk by hand. It's best done in a stand mixer with a whisk attachment. A smaller mixer is better — use a 3.5, 4.5, or 5 qt KitchenAid tilt head mixer if you have one. (See FAQ below for tips on working with a larger mixer bowl.)
• Piping bag and closed star tip: I used a 12" piping bag and small closed star tip (like this one). If you use an open star tip (like a french tip) the star shape will smooth out as the meringue dries.

Crispy Meringue S'mores FAQ

• Do I need to use Swiss meringue? Swiss meringue is the best choice for crispy meringue s'mores because it has the densest air structure. That said, French and Italian meringue do "work" with this. They won't look as pretty and they aren't as good as holding the graham crackers together, but they do "work." Just make sure you're using a 1:2 ratio of egg whites to sugar for a firm meringue.
• I have a different method for making Swiss meringue that I like better, can I use that? Absolutely!
• This small batch meringue is too small for my big mixer, what do I do? As someone with a 7 qt KitchenAid mixer bowl myself, I feel you! I borrowed a smaller tilt-head mixer from my mother in law for the purposes of testing this recipe. If you have a bowl-lift KitchenAid mixer with a 5, 6, or 7 qt bowl, just increase the amount of meringue you're making. Use 3 egg whites and 6 oz sugar, or 4 egg whites and 8 oz sugar. You'll likely have excess meringue at the end but you can pipe it out onto lined sheet pans and let it dry out in the oven — it's great for decorating cakes, pies, and as a snack.
• I don't have cream of tartar, what can I use instead? 1 teaspoon lemon juice or white vinegar. That's ½ teaspoon per egg white. If you can, go for lemon juice over white vinegar, because the vinegar might add a bit of flavor, and no one likes vinegar s'mores.
• What do "stiff peaks" look like? It can be hard to tell when you've reached "stiff peaks" with Swiss meringue because of how heavy it is compared Italian and French meringue. It doesn't triple in size the way the others do. Globs of it might not stand upright on the whisk, they'll kind of lean over. But they shouldn't lean and keep leaning. They'll lean and stay that way. A trick I learned in pastry school is to knock the whisk attachment against the sides of the bowl to get most of the meringue off of it — if you see lots of little peaks sticking up off the wire tines, congrats, you've got stiff peaks. Swiss meringue that has reached "stiff peaks" will hold its shape once piped. So if you pull the whisk up and the meringue is flowing off the whisk, you don't have stiff peaks.
• Can I use a hand mixer to make Swiss meringue? You can but I wouldn't recommend it. Swiss meringue is the densest of the meringues and takes the longest to whip up and requires the most energy from the mixer to whip up correctly. If you have a choice between a hand mixer and a stand mixer, go for the stand mixer. If you only have a hand mixer, just prepare yourself to be whipping the meringue for a good long while, like 10+ minutes without stopping.
• I have Medium, Extra Large, or Jumbo Eggs. How much sugar do I need? You want a 1:2 ratio of egg whites to sugar. Weigh two egg whites, then add 2x that amount in sugar. You want about ⅛ teaspoon cream of tartar per 1 oz egg whites, so adjust accordingly.

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