Boil the cauliflower al dente, seasoned with the crumbled stock cubes. Take a glass bowl and add the oil, the onion and chopped garlic, and put into the microwave oven for 4 minutes at maximum power.
Crumble the tuna and mix it with the chopped hard-boiled egg, the chopped red pepper, the tomato sauce and the sautéed onion and garlic.
Take a dish and arrange one layer of cauliflower, then one layer of the tuna mixture and then another layer of cauliflower. You can top it with the mayonnaise or alioli sauce and grill lightly. Garnish with the prawns sautéed in a little oil.
This type of dish may be served either hot and cold, depending on the time of year or according to taste.