Start by beating the butter, granulated sugar, and brown sugar together until the mixture is pale and fluffy. This step takes around 2–3 minutes with an electric mixer. Don’t rush—it’s the secret to soft, melt-in-your-mouth cookies.
Add the eggs one at a time, mixing well after each addition. Stir in the vanilla extract. The dough should look creamy and smooth, with a slightly glossy finish.
In a separate bowl, whisk together flour, baking powder, and salt. Slowly add the dry mixture to the wet dough, mixing until everything comes together into a soft cookie dough.
Split the dough into three equal parts. Keep one plain for vanilla, stir cocoa powder into the second for chocolate, and mix strawberry extract (plus food coloring if you’d like) into the third. Each dough should have a distinct flavor and color.
On a sheet of plastic wrap, roll each dough portion into a rectangle. Stack them gently—vanilla first, then chocolate, then strawberry on top. Wrap tightly in plastic wrap and chill in the fridge for at least 1 hour. This helps the layers stay sharp during baking.
Preheat your oven to 350°F (175°C). Slice the chilled dough into ¼-inch cookies using a sharp knife. Arrange them on a baking sheet lined with parchment paper, leaving space for spreading. Bake for 12–15 minutes, just until the edges are lightly golden.
Let the cookies cool on the baking sheet for 5 minutes, then transfer them to a cooling rack. They’re beautiful to look at and even better to eat warm or at room temperature.