Mix dries: preheat oven to 375°F. Line two baking sheets with parchment. Combine all your dry ingredients and using a hand or stand mixer on low, mix briefly.
Sand dries + butter together: add in the butter in a few chunks with your mixer on low speed. Sand the ingredients together by allowing them to continually mix on low until the mixture resembles a wet sand - this can take 3-4 minutes and you may need to scrape the bowl once or twice to make sure everything mixes in properly. (Don’t walk away from the mixer or turn up the speed because this mixture will make a full dough if you don’t stop it soon enough!)
Beat in yolks: add in the egg yolks and vanilla and beat again on low speed just until a smooth dough forms. (Do not overmix or your cookies might end up tough and we want to have that nice, tender texture.)
Roll and cut: roll dough out (yes, immediately, there’s no chilling here!) to about ⅛” on a well-floured surface. Cut out your desired shapes in pairs (we love hearts for this occasion!) as each sandwich cookie will need a matching top and bottom. For each of the tops, also use a smaller cookie cutter (about half the size of the bigger one) to cut a hole in the center of the top cookie that the jam will show through (the back end of a pastry tip works as a mini cutter as well). Place the solid bottoms on the prepared baking sheets at least 2” apart and set tops to the side momentarily.
Fill and stack: drop 1 teaspoon of jam on each bottom cookie (definitely err on the side of less jam as it’ll spread out more than you think, and you can always add extra if you need it). Using an offset spatula, the back of a spoon, or a dinner knife, carefully spread the jam out into an even layer, leaving a ¼” border around the edge of your cookie. Add a top cookie over each jammy bottom, ensuring the jam has been spread to cover the full area of the hole in the top cookie.
Bake ‘em: bake for 10-12 minutes, just until there’s a golden-brown edge on the top cookies and the jam has started bubbling.
Cool, share and enjoy: cool cookies all the way to room temperature if you can wait as the butter cookies crisp up very nicely as they cool, and then share the buttery love and enjoy!
⭐ Did you try this tasty recipe? ⭐Please give it a ⭐ rating in the recipe card or leave a comment at the bottom of the page to help others find this sweet recipe. I’d love it if you'd share your treats (literally and electronically!), and tag @mint.and.mallow.kitchen on Instagram or Facebook so I can see your beautiful bakes! Xo, Jocelyn