In a saucepan, combine 1 cup of raspberries with 2 tablespoons of water. Bring to a gentle boil while mashing the raspberries. Cook for about 5 minutes until thickened into a puree. Let cool completely.

In a large bowl, whip 1 cup of softened butter with an electric mixer on medium speed for 3-4 minutes until light and fluffy.

Gradually sift in 4 cups of powdered sugar while mixing on low speed and then increase to medium for 2 minutes.

Add 2 tablespoons of raspberry puree and 1 teaspoon of vanilla extract, mixing on low until combined.

Slowly add 2-4 tablespoons of heavy cream, mixing on low, then scrape the bowl sides and add a pinch of kosher salt. Whip on medium-high for 4-5 minutes.

Use the frosting immediately or store in an airtight container in the refrigerator for up to 7 days.