Preheat the oven to gas 6 / 200C / 400°F
Prick the potatoes all over with a fork, brush with 1/2 a tablespoon of the oil and arrange on a baking sheet. Bake until tender, around 1 - 1 & 1/2 hours. You can also bake in the microwave on full power for 7 - 12 minutes depending on the wattage. Mine take 10 mins at 800W
When the potatoes are almost tender, heat the remaining tablespoon of oil in a large frying pan over a medium high heat. Add the courgette, squash, mushrooms, onions & salt and pepper and cook, stirring occasionally, until just tender and golden brown, around 6 minutes
Preheat the grill / broiler. Halve the potatoes, transfer to a baking dish cut side up and top with the vegetable mixture. Pour some warmed marinara sauce over the potatoes then top with as much cheese as you like. Grill until the cheese is melted and bubbly, 2 or 3 minutes, then transfer to plates and serve
For the marinara, place the tomatoes, tomato paste, minced garlic, oregano, salt, and pepper in a blender and blitz until smooth. Saute the finely chopped onion in olive oil for 2 minutes in a large frying pan. Add the blended tomato sauce, basil and white wine. Simmer for 30 minutes, stirring occasionally. This makes twice as much as needed in this recipe but you can freeze the half you don't need for another time
Instead of marinara you can try my tomato-free tomato sauce, recipe in my profile
https://cookpad.com/us/recipes/332955-vickys-tomato-free-tomato-pasta-sauce-ketchup-gf-df-ef-sf-nf
My Bean Sprout 'Pasta' recipe uses the same marinara recipe
https://cookpad.com/us/recipes/361521-vickys-bean-sprout-pasta-and-marinara-sauce-gf-df-ef-sf-nf
