Preheat oven to 350°F (convection). Beat room-temperature butter in a stand mixer or by hand for 3–5 minutes, until the butter turns slightly off-white and creamy.

Add granulated sugar and beat with the butter until light and fluffy, about 2 minutes.

Add the egg and vanilla extract, mixing until fully combined and smooth.

Add flour, baking soda, baking powder, and Valentine sprinkles. Gently fold until a soft cookie dough forms.

Using a 1/3 cup scoop (or desired size), place a single dough ball on a baking tray. Bake this test cookie first to check spread and oven temperature, adjusting if needed.

Place the remaining dough balls on the tray, evenly spaced. Flatten slightly if desired. Bake for 12–14 minutes (for 1/3 cup scoops).

For perfectly round cookies, swirl a circular cup or bowl around each cookie while still warm. Let cookies rest on the tray for about 10 minutes before transferring.

Beat butter until smooth and slightly off-white. Add powdered sugar, heavy cream, and vanilla extract. Whip until fluffy and smooth.

Frost cooled cookies and finish with Valentine sprinkles. Store in the fridge for up to 10 days or at room temperature for up to one week.