Preheat your oven to 350 degrees Fahrenheit. Line a large rimmed baking sheet with parchment paper so the cookie does not stick.

In a large mixing bowl, cream together the softened butter, granulated sugar, and brown sugar. Use an electric mixer on medium high speed until the mixture is light and fluffy, which usually takes about 2 to 3 minutes.

Add the eggs one at a time, beating well after each addition. Stir in the vanilla extract.

In a separate bowl, whisk together the flour, baking soda, and salt. Gradually add the dry ingredients to the wet ingredients, mixing on low speed until just combined. Be careful not to overmix, as this can make the cookie tough.

Fold in the chocolate chips and half of your festive sprinkles by hand with a spatula.

Transfer the dough to the prepared baking sheet. Using your hands or a spatula, shape the dough into a large heart. Aim for a thickness of about 1/2 inch to 3/4 inch. If the dough is sticky, lightly flour your hands.

Bake for 18 to 22 minutes or until the edges are golden brown but the center still looks slightly soft. It will firm up as it cools.

Let the cookie cake cool completely on the pan before attempting to move it or decorate it. This is crucial for maintaining the heart shape.

Once cool, pipe borders of buttercream frosting around the edges and add your remaining sprinkles.