Make the sauce first - warm some olive oil and add the onions. Cook gently until soft, this will be about 10 minutes.
Add the carrots, herbs, and a little water to cover. Simmer for 15 minutes.
Add the cooked beetroot, cider vinegar, and blend to a smooth and thick consistency. Then allow this to cool a little.
Drain and flake the salmon onto a dish, cover with the wilted spinach or sliced courgette, and cover with the sauce.
Mix together the breadcrumbs, yeast flakes, and herbs.
Sprinkle the breadcrumb mix over the fish mixture.
Bake in the oven at 180 degrees or slowly grill to heat through and brown the breadcrumbs.