Purple Confetti Chocolate Squares

1. Natural Purple Food Colouring: Place cabbage in large pot; pour in enough water to come halfway up side of cabbage. Bring to boil; reduce heat to medium and simmer for 15 minutes. Using slotted spoon, remove cabbage (reserve cabbage for another use). Simmer cooking liquid in pot for 10 to 12 minutes or until thickened to the consistency of food colouring. Stir in baking soda; set aside.
2. Purple Confetti White Chocolate Squares: Preheat oven to 325°F (170°C). Grease 8-inch (20 cm) square baking pan.
3. Using wooden spoon, in large bowl, combine cake mix, sprinkles, egg, brown sugar, vegetable oil and oat milk until blended. Stir in chocolate chips; spread into prepared pan.
4. Bake for 25 to 27 minutes or until golden brown and toothpick inserted in centre comes out clean; let cool completely on rack.
5. Blend vanilla frosting with 1 tsp (5 mL) natural purple food colouring in bowl; spread frosting over cake. Cut into squares.

The purple colouring is best made with fresh cabbage, as the cabbage flavour intensifies as the cabbage ages.