Adjust an oven rack to the middle of the oven and preheat to 350F [180C]. Line three baking sheets with parchment paper.

In a medium bowl, combine the flour, baking soda, and salt.

In a food processor, pulverize the strawberries into a powder.

In a stand mixer, beat the butter on medium speed until creamy, about 1 minute. Add the sugar and beat until light and fluffy, 2 to 3 minutes. Add the egg, yolk, and vanilla, and beat until combined.

Add the flour mixture and beat on low speed until just combined.

Dump the dough onto a work surface and divide it into three equal portions.

Add one-third of the dough back into the mixer and add the powdered strawberries and food coloring, if using. Mix on low speed until combined, then remove the dough and wipe out the bowl.

Add another third of the dough to the mixer and add the cocoa powder. Mix on low speed until combined.

Pinch a small portion (about 1/2 oz [15 g]) of each of the three doughs and press them together gently. Roll each piece into a cookie scoop or a ball, and roll in sprinkles or granulated sugar.

Place 6 or 7 cookies on each sheet pan. Bake one pan at a time, rotating halfway through, until the sides are set and the cookies are puffed, 10 to 11 minutes.

Transfer the sheet pan to a wire rack and cool for 5 to 10 minutes on the pan before removing to cool completely on the wire rack.