These adorable lemon blueberry mini muffins each have one whole blueberry in the center. They're so cute and just as fun to make as they are to eat. Perfect for a quick snack break or as a picnic treat!
Soak poppyseeds in buttermilk at room temperature for 30 minutes. Bring egg to room temperature.
Whisk dry ingredients, including lemon zest, together in a bowl. Set aside.
Whisk room-temperature egg into the buttermilk and poppyseed mixture along with the sugar. Slowly drizzle in melted butter, whisking well until thoroughly combined.
Pour liquid ingredients into dry ingredients and gently fold together with a spatula just until combined. Some lumps are okay. Do not overmix.
Cover muffin batter and let rest for 30-60 minutes.
While muffin batter rests, preheat oven to 400°F. Line a mini muffin tin with muffin liners.
Use a 2 teaspoon scoop to portion muffin batter into lined mini muffin tin. Press a single blueberry deep into the center of each muffin, then use a toothpick to push (or twirl) the batter over the blueberries to hide them.
If you scrape the muffin batter flat on the edge of the bowl (as opposed to heaping scoops) before dropping it into the muffin tins you will get exactly 24 mini muffins.Push each blueberry down until it's suspended in the middle of the mini muffin. Don't push them all the way to the bottom; you don't want soggy muffin bottoms!
Rub granulated sugar and lemon zest together in a bowl to use for muffin topping. Top each muffin with ¼-½ teaspoon lemon sugar.
Bake mini muffins for 13-15 minutes at 400°F. The muffins will not brown much on top, but a toothpick inserted should come out clean (as long as you don't piece a blueberry).
Let cool in muffin tin 5-10 minutes, then remove to a rack to finish cooling completely.
RECIPE NOTES
Store in an airtight container for up to 5 days.
My favorite substitute for buttermilk is buttermilk powder. Mix 1 tablespoon in with the dry ingredients and use 57 grams warm whole milk or warm water in place of the buttermilk. America's Test Kitchen even approves of this swap (h/t to recipe tester Beth for this tip!). I tested this myself and it worked remarkably well, way better than I expected! I wouldn't say it's a perfect buttermilk substitute for every recipe, but it does work just fine here. As a bonus: Buttermilk powder can last a long time in the fridge, much longer than fresh buttermilk.
I don't recommend using a stand mixer or hand mixer for these mini muffins unless you have limited dexterity preventing you from stirring comfortably. One of the biggest reasons muffin recipes fail is because of over-mixing. The high speed and power of most mixers will produce tough muffins. If you need to use a mixer, use the lowest possible setting and stop mixing as soon as the batter is combined.
Let these buttermilk lemon-blueberry muffins cool completely before eating. They're small and delicate with an unstable center; if you try to peel the paper off while they're warm, the paper won't release cleanly.