In a large mixing bowl, cream the softened butter and sugar together until the mixture becomes light and fluffy. Add the egg and vanilla extract, beating until fully incorporated and smooth. This creates the base for your cookie dough.
In a separate bowl, sift together the all-purpose flour, cocoa powder, baking powder, and salt. Gradually add this dry mixture to the wet ingredients, blending slowly until a soft and pliable dough forms. Ensure the dough is well-mixed but not overworked.
Preheat your oven to 350°F (175°C) and prepare a baking sheet by lining it with parchment paper. Roll the dough into small, even-sized balls, then flatten them slightly with your hands. Use a flower-shaped cookie cutter to create beautiful, uniform shapes, and gently lift each cookie onto the baking sheet.
Arrange the cookies on the baking sheet, leaving enough space between them to expand slightly during baking. Place the tray in the preheated oven and bake for 12–15 minutes, or until the edges become firm and crisp while the centers remain tender.
Remove the cookies from the oven and allow them to rest on the baking sheet for about 5 minutes to firm up. Transfer them carefully to a wire rack to cool completely. Serve these delightful cocoa flower cookies with a hot beverage or store them in an airtight container to maintain their crunch for up to a week.