Combine the softened butter and powdered sugar in a mixing bowl. Using a stand or hand mixer, beat until smooth and creamy, with a pale, fluffy appearance, approximately 2-3 minutes.
Add the flour to the butter mixture gradually, mixing on low speed until the dough starts to come together and looks crumbly but holds together when pressed. Turn off the mixer.
Gently fold the mashed strawberries into the dough, mixing with a spatula until evenly distributed, and the dough becomes soft but manageable. The strawberries should create a pink hue throughout the mixture.
Turn the dough onto a lightly floured surface. Roll it out to about 1/2-inch thickness using a rolling pin. Use a cookie cutter or knife to cut out individual cookies and place them on a parchment-lined baking sheet.
Bake in a preheated oven at 350°F (175°C) for 15 minutes, or until the edges are just lightly golden. The cookies should be firm but still tender.
Remove the cookies from the oven and allow them to cool on the baking sheet for 5 minutes before transferring to a wire rack. Cool completely before serving to set the texture.
