Step 1:
Boil water in your jug ready to add later.
Step 2:
Meanwhile, heat a large skillet/pan (that has a lid.) Add the oil and sauté the onion & red onion until translucent, about 5 minutes. Add sliced mushrooms, cook for 3min, the garlic and cook 30 seconds.
Step 3:
Into the skillet add the pasta, pepperoni, chopped tomatoes, red & green peppers, as well as the rosemary and salt and pepper. Pour the hot water over all and stir to prevent sticking. Bring to a boil quickly and immediately reduce to a simmer, if using milk, add it now.
Step 4:
Cover the skillet and simmer for 12 minutes, stirring occasionally to prevent sticking. If using cream stir it in now (can use cream and milk if you choose) then add cheese. The pasta dish will thicken upon standing,
Step 5:
Add blob of thick Greek yoghurt (or sour cream) and sprinkle with (more) grated cheese and garnish with parsley.
Delish!