In an extra-large bowl beat 1 cup softened butter with a mixer on medium speed 1 to 2 minutes or until creamy. Beat in 1 cup powdered sugar. Add 2 Tbsp. heavy cream, 1 tsp. vanilla, 1/4 tsp. almond extract (optional), and a dash salt; beat on low until combined. Gradually beat in 3 cups powdered sugar just until combined. Beat on medium speed 5 minutes or until fluffy, scraping bowl as needed. Add additional 1 Tbsp. heavy cream; beat on high 1 minute more.