Preheat the Oven:

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

Prepare the Cupcake Batter:

In a medium bowl, whisk together flour, baking powder, and salt.

In a large bowl, cream together the butter and sugar until light and fluffy.

Beat in the eggs one at a time, then add the vanilla extract.

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

Add the Raspberry Swirl:

Fill each cupcake liner about halfway with the batter.

Add a small spoonful of raspberry preserves or a few fresh raspberries to each cupcake.

Add more batter to cover the raspberries, filling each liner about 2/3 full.

Use a toothpick or skewer to gently swirl the raspberry preserves into the batter.

Bake the Cupcakes:

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

Allow the cupcakes to cool in the tin for a few minutes before transferring to a wire rack to cool completely.

Prepare the Frosting:

In a large bowl, beat the softened butter until creamy.

Gradually add the powdered sugar, beating until smooth.

Mix in the vanilla extract and heavy cream, one tablespoon at a time, until the frosting reaches the desired consistency.

Frost the Cupcakes:

Once the cupcakes are completely cool, frost them with the vanilla frosting using a spatula or piping bag.