01 -
In a medium pot, stir together raspberries and sugar over medium heat. Stir constantly for about 10 minutes until it becomes syrupy and the berries break apart. Strain through a sieve and set aside to cool.
02 -
Cut frozen raspberries into smaller chunks and place back in the freezer. In a bowl, combine the flour, salt, baking powder, and cornstarch. Mix water with the remaining cornstarch separately until smooth.
03 -
Blend butter and sugar until fluffy (around 2-3 minutes). Add the cornstarch-water mix, milk, and the cooled syrup from earlier. Toss in the dry ingredients bit by bit, followed by food coloring. Lastly, stir in frozen raspberry pieces until swirled.
04 -
Let the dough chill in the freezer for at least an hour. Heat oven to 325°F. Form dough into balls, coat in the reserved sugar, and put on a parchment-covered baking tray, spacing 3-4 inches apart. Bake for 15 minutes. Use a spatula to quickly reshape the cookies, then cool on the tray for 5 minutes before moving to a rack.