Design Eat Repeat

0 Preheat oven to 350℉. If butter hasn't been softened you can place in microwave for 10 seconds to *slightly* soften it.
1 In a large bowl, cream together softened unsalted butter (1 cup, i.e., 2 sticks) and granulated sugar ([adjustable]1 cup) on medium speed for 20-30 seconds; do not overbeat. While the mixer is still on medium speed, add in egg (1 large), vanilla extract (2 teaspoons), and almond extract (1 teaspoon[/adjustable]).
2 Once mixed, add in baking powder ([adjustable]1 ½ teaspoons), salt (½ teaspoon[/adjustable]), and all-purpose flour ½ cup at a time ([adjustable]2 ¼ [/adjustable]cups total). Be sure to measure your flour properly using the spoon & level method, as adding too much can result in dry bars. Mix until all flour disappears, typically 20-30 seconds.
3 Spray a round metal 12" cookie cake pan with cooking spray, then line the bottom with parchment paper (having the grease underneath the paper will help the paper stay down).
4 Drop the dough into 1 tablespoon sized chunks into the prepared pan. Use your hands or a spatula to press down the dough until it covers the pan and is smooth around the edges.Tip: If the dough is sticky, you can place another piece of parchment paper on top and continue pressing down. 
5 Bake cookie cake at 350℉ for 18-20 minutes until edges are lightly browned. The trick to a soft sugar cookie cake is to take it out right when you see the TINIEST amount of brown around the edges. The center may look underdone and this is okay; the cake will continue to bake in the hot pan when cooling.
6 Allow to cool completely before frosting (you can put the pan in the fridge on a cooling rack to speed this up).
To Make Frosting:
9 In a large bowl, beat softened unsalted butter ([adjustable]½ [/adjustable]cup, i.e. [adjustable]1 [/adjustable]stick) on medium speed using a hand or stand mixer (with paddle attachment) for 1-2 minutes (until light and creamy).
10 Keeping the mixer on medium speed, slowly add in vanilla extract ([adjustable]2 teaspoons), almond extract (½ teaspoon), and powdered sugar (2 ¾ cups[/adjustable]). Once incorporated, turn the mixer to high speed and beat for 2 minutes until light and fluffy. Add milk ([adjustable]1 [/adjustable]tablespoon) and beat for 30 seconds. Add an additional [adjustable]1 [/adjustable]tablespoon of milk if frosting seems too thick to spread.
11 If using sprinkles, add them immediately after frosting. If you wait too long, the frosting will set and the sprinkles won't stick.
Storage:
15 If not eating same day, cover with plastic wrap and store in refrigerator for 2-3 days. This sugar cookie cake is also amazing frozen for 1-2 months (any longer and it tends to dry out).