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 ([adjustable]1 cup, i.e. 2 sticks) and granulated sugar (1 cup[/adjustable]) on medium speed for 20-30 seconds. While mixer is still on medium speed, add in egg ([adjustable]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 at time ([adjustable]2 ¼ cups total[/adjustable]). 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. You do not need to beat/mix this any longer than it takes to mix in the flour. When pinched between your fingers, dough should be similar to a playdoh consistency and not be very sticky. Refer to photo above in post for how dough should look.
3 Spray a metal 9×13 pan with cooking spray, then line pan 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.Tip: If the dough is sticky, you can place another piece of parchment paper on top and continue pressing down. To get clean edges, you can fold down the sides of the parchment paper and press like shown in the post above.
5 Bake bars at 350℉ for 14-16 minutes. The trick to soft sugar cookie bars is to take them out right when you see the TINIEST amount of brown around the edges. The center may look underdone and this is okay; the bars 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 cup, i.e. 1 stick[/adjustable]) 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 cups[/adjustable]). Once incorporated, turn mixer to high speed and beat for 2 minutes until light and fluffy. Add [adjustable]1 tablespoon[/adjustable] of milk and beat for 30 seconds. Add the remaining [adjustable]1 tablespoon[/adjustable] 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.
Cutting & Storage:
14 Refer to the tips in the post above on how to cut the perfect squares!
15 If not eating same day or within 3-4 hours, place in airtight container and store in refrigerator for 2-3 days. These bars are also amazing frozen for 1-2 months (any longer and they tend to dry out).