Preheat your oven to 350°F and line a baking sheet with parchment paper. While the oven heats, measure out all your ingredients and place them on your work surface—this ensures smooth, uninterrupted baking once you start mixing. I always make sure my egg is at room temperature because it incorporates more evenly into the butter mixture, creating a lighter, more tender crumb.

In a large mixing bowl, combine the butter, margarine, and sugar. Beat them together on medium speed for 2-3 minutes until the mixture becomes pale, fluffy, and noticeably lighter in color. This creaming process incorporates air into the fat, which helps the cookies rise slightly and creates a tender texture. Stop occasionally to scrape down the bowl sides to ensure everything is evenly combined.

Add the room-temperature egg, corn syrup, vanilla, butter extract, and almond extract to the creamed mixture from Step 2. Beat on medium speed for 1-2 minutes until everything is well combined and the dough looks smooth and slightly glossy. The corn syrup adds subtle sweetness and helps keep these cookies tender, while the butter and almond extracts give them that professional bakery flavor that makes people ask for your recipe.

In a separate small bowl, whisk together the flour, baking soda, and salt. Add this dry mixture to the wet ingredients from Step 3 and stir on low speed (or by hand with a wooden spoon) until just combined—stop mixing as soon as you see no white flour streaks. Overmixing at this stage develops gluten and makes cookies tough, so resist the urge to keep stirring once the dough comes together.

Using a cookie scoop or tablespoon, portion the dough from Step 4 into balls and place them on the prepared baking sheet, spacing them about 2 inches apart. Working quickly, gently press a generous pinch of your sprinkle mix (hearts and nonpareils combined) onto the top of each dough ball, applying enough pressure so they stick but not so much that you compress the dough. For Valentine's Day, I like using a mix of heart-shaped sprinkles with traditional nonpareils so each cookie has visual texture and variety.

Bake the cookies for 7-9 minutes if you made smaller balls, or 9-11 minutes if you made larger ones. The edges should be just barely set and pale golden—they'll look slightly underbaked, but that's intentional and keeps them tender and soft. Remove from the oven and let the cookies cool on the baking sheet for 5 minutes (they'll continue cooking slightly from residual heat), then transfer to a wire rack to cool completely.