Preheat oven to 350℉ (180℃)
Sift or whisk together flour, baking powder and salt.
2 Cups All-purpose flour, ¾ teaspoon Baking Powder, 1 teaspoon Salt
Place butter and sugar in bowl of a stand mixer. Using the paddle attachment begin mixing on medium speed. Continue to mix until butter and sugar mixture is light and fluffy (approximately 2 - 3 minutes). Note: a hand mixer may also be used
1 Cup Butter, ¾ Cup Granulated Sugar (measure #1)
Add vanilla to mixing bowl and mix for another 20 seconds.
1 teaspoon Vanilla extract
Add the flour, baking powder and salt mixture to mixing bowl. Mix for 20 - 30 seconds.
Remove bowl from the mixer and, using a silicone spatula, mix the dough briefly. Note: the dough will be crumbly.
Pour dough into the prepared pan. Using your hands, lightly press dough down so it evenly covers the bottom of pan.
Bake for 12 minutes.
Place on a cooling rack. Cool for 10 minutes. Proceed with making the topping.