In a blender or food processor, purée strawberries until liquefied. Push puréed strawberries through a fine-mesh sieve. (There should be approximately ¾ cup purée.)
In a small saucepan, boil purée until it reduces to ¼ cup, stirring occasionally as it foams up, 15 to 20 minutes. Transfer purée to a medium bowl, and refrigerate for several hours, or until very cold.
In a large bowl, beat together butter and 1½ cups confectioners’ sugar with a mixer at high speed until combined. Add cold purée, cream, strawberry extract, and salt, beating until incorporated. Add remaining 1½ cups confectioners’ sugar, beating until light and fluffy. Use immediately, or store for up to a day in an airtight container in the refrigerator.
Recipe by TeaTime Magazine at https://teatimemagazine.com/lemon-cupcakes-with-fresh-strawberry-frosting/