Preheat oven to 350F and grease a 12-inch pizza pan or cast iron skillet.

Cream butter, brown sugar and granulated sugar together until light and fluffy, about 2 minutes.

Beat in egg and vanilla until smooth.

Whisk flour, baking soda and salt in a separate bowl, then stir into the butter mixture just until combined.

Fold in chocolate chips.

Press dough evenly into the prepared pan, leaving a slightly thinner edge so it bakes evenly.

Bake 18 to 22 minutes, until the edges are golden and the center looks set but still soft (it will firm as it cools; do not wait for the middle to look fully baked).

Cool the cookie cake completely in the pan, about 30 minutes, before decorating.

Beat butter, powdered sugar, vanilla and milk into a thick buttercream, dividing and tinting portions if using team colors.

Pipe a football outline and laces in the center, or write a score in team colors around the edge.

Slice into 12 wedges to serve.