I am planning to make a lemon curd blueberry layer cake for my daughters birthday party this weekend. My question is, can I use coloring gel to make this frosting recipe purple or will the ingredients cause it to ruin it?
1 cup (2 sticks)(227 g) unsalted butter, softened
2 teaspoons (10 ml) lemon zest
5 cups (625 g) icing sugar, sifted
2 tablespoons (30 ml) fresh lemon juice
1/4 cup (60 ml) whipping cream (35% cream)