Preheat Oven: Start by preheating your oven to 350°F (175°C). Line a cupcake pan with paper liners.

Mix Dry Ingredients: In a bowl, whisk together flour, baking powder, baking soda, and salt.

Cream Butter and Sugar: In a separate bowl, beat the butter and sugar until light and fluffy.

Add Eggs and Vanilla: Beat in the eggs, one at a time, then stir in the vanilla extract.

Combine Wet and Dry Ingredients: Alternately add the dry ingredients and sour cream to the butter mixture, starting and ending with the dry ingredients.

Fold in Pineapple: Gently fold in the crushed pineapple.

Fill Cupcake Liners: Spoon the batter into the cupcake liners, filling each about two-thirds full.

Bake: Bake for 18-20 minutes, or until a toothpick inserted into the center comes out clean.

Cool Cupcakes: Allow the cupcakes to cool in the pan for 5 minutes, then transfer to a wire rack to cool completely.

Make the Frosting: For the frosting, beat the butter until smooth. Gradually add powdered sugar, pineapple juice, and vanilla extract, beating until creamy.

Frost Cupcakes: Once the cupcakes are cool, frost them with the pineapple buttercream.

Decorate (Optional): Garnish with a small piece of pineapple or a cherry on top for an extra tropical touch.