Instant Pot Pineapple Upside Down Cake

Melt 4 tablespoons Unsalted Butter and mix with 1/2 cup Brown Sugar in a small bowl until smooth. Pour evenly into the bottom of a greased Instant Pot-safe pan.
Place 8 slices Pineapple over the butter and sugar mixture. Fit them snugly to cover the base.
Make the Cake Batter: In a separate bowl, whisk together 1 1/2 cups All-Purpose Flour, 1 cup Granulated Sugar 1 1/2 teaspoons Baking Powder, and 1/4 teaspoon Salt. In another bowl, mix 3 large Eggs, 1 teaspoon Vanilla Extract , and 1/2 cup Milk then combine with the dry ingredients until smooth.
Pour the batter carefully over the pineapple slices, spreading evenly.
Cover the pan with foil and place on a trivet inside the Instant Pot. Add 1 cup water to the pot, seal, and cook on high pressure for 35 minutes.
Allow natural pressure release for 10 minutes, then carefully remove the pan. Let the cake cool for 5–10 minutes before inverting onto a serving plate.
Slice and serve warm, optionally with whipped cream or ice cream.