Preheat oven to 350 degrees Fahrenheit. Grease a 9-inch round cake pan and set aside (optionally, add a round piece of parchment to the bottom for easy removal later).

In a bowl, add butter and granulated sugar. Using a hand mixer (or stand mixer) beat until creamed and fluffy, about 1-2 minutes. Add eggs and vanilla extract and mix until creamy and smooth.

In a separate bowl, add dry ingredients: flour, baking powder, and salt. Whisk to combine and remove clumps.

Add half of dry ingredients to butter mixture and gently mix until just incorporated. Add half of milk and gently mix to incorporate. Repeat once more to incorporate remaining dry ingredients and milk. Do not overmix.

Pour batter into prepared 9-inch cake pan. Bake for about 26-32 minutes, or until a toothpick inserted into the center comes out with crumbs, not batter. Or, gently press into the top of the cake with a finger. If cake springs back right away, it's done. If it leaves an indent, your cake needs more time.

Cool cake in pan on a wire cooling rack. Once cooled, turn out onto a serving plate and dust the top with confectioner's sugar just before serving.