In a large bowl, beat together butter and salt with a mixer at medium speed until creamy, approximately 2 minutes. Reduce speed to low; gradually beat in confectioners’ sugar until well combined, stopping to scrape sides of bowl. Increase speed to medium; beat in reduced Champagne and vanilla extract until fluffy, 3 to 4 minutes. Use immediately.
Recipe by TeaTime Magazine at https://teatimemagazine.com/strawberry-filled-champagne-cake/