In a large bowl, beat the butter and sugar for 3 minutes until light and fluffy. Beat in the egg, egg yolk, vanilla and almond extract until smooth.
Whisk the flour, cornstarch, baking powder and salt in a separate bowl, then mix into the butter mixture on low just until a soft dough forms.
Scoop the dough into 1/4 cup balls and flatten each one into a thick disc about 3/4 inch tall. Place on a parchment-lined tray and chill for 30 minutes.
Preheat the oven to 350°F and transfer the chilled dough discs to parchment-lined baking sheets, spacing them 2 inches apart. Bake for 9-11 minutes, until puffed and set but still pale on top.Let them cool on the baking sheets for 10 minutes, then transfer to a wire rack to cool completely.
For the frosting, beat the butter, powdered sugar, oat milk, almond extract, vanilla and salt for 2-3 minutes until smooth and fluffy. Add the food coloring a drop at a time until you get a soft pastel pink.
Spread a thick layer of frosting over each cooled cookie with an offset spatula, swirling the top. Refrigerate for 30 minutes and serve chilled for that soft, bakery style bite.