Preheat the oven to 350?F (175?C) and line a muffin tin with cupcake liners.

In a mixing bowl, whisk together flour, sugar, baking powder, baking soda, and salt.

In another bowl, cream the softened butter, then add eggs, buttermilk, and vanilla extract. Mix well.

Gradually add the dry ingredients to the wet ingredients, mixing until just combined.

Fill each cupcake liner about 2/3 full with the batter.

Bake for 18-20 minutes or until a toothpick inserted comes out clean. Let cool completely.

In a saucepan, combine pureed pineapple, sugar, and egg yolks. Cook over medium heat, stirring constantly until thickened.

Remove from heat and stir in butter and lemon juice until smooth. Let cool.

In a mixing bowl, beat together powdered sugar, softened butter, milk, and vanilla extract until smooth and creamy.

Once the cupcakes are cool, make a small hole in the center of each cupcake and fill with pineapple curd.

Frost the cupcakes with the prepared frosting.