This is adapted from a recipe I used to make in my high carbage days.
It is an economical, tasty family dish.

Serves 4

400g (14 oz?) can tuna
4 tablespoons mayonnaise
About 1 kg (32 oz) cauliflower
2 400g cans chopped tomatoes
4 spring (green) onions
120-240g (4-8oz) grated cheese


Steam, boil or microwave cauliflower until softened. Mash, and add butter to taste.
Simmer tomato with spring onion until "dryish." Add a slurp of olive oil if you wish.
Mix tuna with mayo.
Grease a casserole dish.
Layer ½ the mashed cauli into the dish, followed by ½ the tuna mix, followed by a "small" half of the tomato. Repeat the layers and sprinkle with the cheese.
Bake in a moderately hot oven for 20-30 minutes, or until browned.

Total carbs (assuming 8 oz cheese):
40 (after fibre subtracted)
You could decrease the carb count by using slices of fresh tomato instead of canned.