Swiss Almond Carrot Cake (Aargauer Rueblitorte) Recipe

Ingredients

• 1 teaspoon butter
• 4 eggs, separated
• 1 cup white sugar
• 2.25 cups peeled and grated carrots
• 2.25 cups ground almonds
• 1 lemon, zested and juiced
• 0.5 cup all-purpose flour
• 1 teaspoon baking powder
• 1 pinch salt
• 5 ounces marzipan
• 1 drop green gel food coloring, or as needed
• 1 drop orange gel food coloring, or as needed
• 1 cup confectioners' sugar
• 1 tablespoon fresh lemon juice, or more to taste