Melt butter in a saucepan over medium heat. Cook 5–7 min, watching closely, until it foams and turns golden brown. Remove from heat and pour into a bowl, scraping brown bits. Cool to room temp, stirring occasionally.
Add sweetened condensed milk to cooled butter; stir until well mixed. Set aside
Beat whipping cream in a large bowl until stiff peaks form. Fold 1 cup whipped cream into butter mixture. Add remaining butter mixture and toffee bits, folding gently until combined
Pour mixture into 2 (9×5-inch) loaf pans or 1 (8-inch) square baking pan. Freeze 6 hours or until firm
