Place strawberries in food processor, process until pureed. In bowl with mixer, beat together butter and salton medium speed until light and fluffy. Reduce speed and slowly add powder sugar, beat until well combined. Add vanilla and 3 tablespoons strawberry puree (save remaining puree), mix until blended. Do not overmix or frosting will incorporate too much air. Frosting consistency should be dense and creamy, like ice cream.