Wow!! That looks amazing! Did you use beetroot juice or mashed beetroot?
I used the liquid left from boiling beetroot. I cooked peeled beetroots in a pot of water with a splash of white vinegar and was left with the dark magenta water. It colours the crust nicely but there's no beetroot flavour. I'd probably have to add chopped beetroot for that.I'm stumped as to why the inside isn't red. It'd be a good high school science question!