In a medium bowl, whisk together the flour, cornstarch, baking powder, baking soda and salt. Set aside.
In a large bowl, beat the dairy free butter and sugar for 2-3 minutes until pale and fluffy. Beat in the egg, dairy free yogurt, vanilla and almond extract until smooth.
Add the dry ingredients and mix on low speed until a soft, slightly sticky dough forms. Cover and chill for 1 hour, which makes the dough easy to shape and keeps the cookies thick.
Preheat the oven to 350°F and line two baking sheets with parchment paper. Roll the dough into 2 tablespoon balls, place them 2 inches apart and press each one into a 1/2 inch thick disc with the bottom of a glass.
Bake for 9-11 minutes, until the cookies are puffed and set but still pale with no browning. Cool on the sheet for 5 minutes, then move to a wire rack to cool completely.
For the frosting, beat the dairy free butter until creamy, then add the powdered sugar, oat milk, vanilla and pink food coloring. Beat for 2-3 minutes until light, fluffy and smooth.
Spread a thick layer of frosting over each cookie and top with sprinkles right away. Let the frosting set for 30 minutes, then store airtight, since the cookies get even softer by the next day.