These snickerdoodle chocolate chip cookies are so soft and chewy with a warm cinnamon sugar coating. It's everything you love about snickerdoodles and chocolate chip cookies in one!
Melt and cool butter. In a large, microwave-safe bowl, melt butter in 15-20 second bursts in the microwave. This is the bowl you'll make your cookie dough in, so give yourself plenty of extra room. Stop when there are a few solid pieces of butter left — stir gently until they melt. Set aside to cool 25-30 minutes (you should see some butter starting to solidify around the very edges).
Mise en place. While butter cools, combine flour, salt, cream of tartar, and baking soda in a bowl. In a separate bowl mix together sugar, cinnamon, and cayenne for topping and set aside.
Whisk both sugars into cooled butter until it begins to thicken and is very smooth and pale in color, about 1-2 minutes (seriously, set a timer!). Add egg yolks one at a time, whisking for at least 30 seconds after each. Add the vanilla and whisk vigorously 60 seconds more.
Add the flour mixture all at once. Switch to a spatula and stir gently but firmly. At first it will seem like there is too much flour, but keep stirring and folding the mixture over itself and it will combine. When there is still a bit of flour in the bottom of the bowl, add the chocolate chips and continue stirring until you have a cohesive dough.
Portion the dough. Use a #40 (1½-2 tablespoon) scoop to portion the dough onto a quarter sheet pan lined with parchment paper. Roll each dough ball in your hands to smooth it out into a round ball, then roll each ball in cinnamon sugar and place back on the parchment paper. The dough balls will be quite close together, that's okay. Cover and chill 1 hour.
Preheat oven to 400°F toward the end of the hour.
Re-roll in cinnamon sugar. Right before baking, roll each dough ball in the cinnamon sugar mixture again, then arrange on a parchment lined sheet pan at least 3 inches apart. I can usually fit 6, maybe 8 cookies per pan. Don't crowd them.
Bake 8-9 minutes. They should look slightly underdone in the middle. Remove from the oven and immediately use a round cutter or upside down glass jar to scoot them into shape (scooting is optional!). Let cool on the sheet pan 5 minutes before transferring to a cooling rack to cool completely.
RECIPE NOTES
If you don't have baking soda and cream of tartar, you can sub in 2 teaspoons baking powder. You'll have a less dramatic rise, and will miss the subtle tangy flavor expected in snickerdoodles, but most people probably won't notice a difference.
Resting time includes time for melted butter to cool and time for cookies to chill in the fridge.
To freeze: Roll cookies once in cinnamon sugar, then freeze on a sheet pan. Transfer frozen dough balls to airtight container and store in the freezer for up to 3 months.
To bake from frozen: Defrost at room temperature 20-30 minutes (just enough to soften the outside), then roll in cinnamon sugar. Bake 10-12 minutes at 400°F.