Preheat Oven:

Preheat your oven to 350°F (175°C). Line a cupcake pan with cupcake liners.

Mix Dry Ingredients:

In a bowl, whisk together the flour, baking powder, and salt. Set aside.

Cream Butter and Sugar:

In a large mixing bowl, beat the butter and sugar with an electric mixer until light and fluffy, about 2–3 minutes.

Add Eggs and Vanilla:

Beat in the eggs one at a time, followed by the vanilla extract.

Incorporate Wet and Dry Ingredients:

Gradually add the dry ingredients to the butter mixture, alternating with the milk and strawberry purée. Mix until just combined.

Fill and Bake:

Divide the batter evenly among the cupcake liners, filling each about 2/3 full.

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

Let the cupcakes cool completely on a wire rack.

Prepare the Buttercream:

Beat the butter until creamy. Add the powdered sugar one cup at a time, alternating with the strawberry purée and vanilla.

Mix until smooth and fluffy. Add a pinch of salt to balance the sweetness.

Frost the Cupcakes:

Transfer the buttercream to a piping bag fitted with your favorite tip and frost the cupcakes. Alternatively, use a spatula to spread the frosting.