Preheat oven to 400°F (200°C). Place garlic cloves (unpeeled) on a small piece of foil, drizzle with 1 tsp olive oil, wrap loosely and roast on a baking sheet for 20 minutes, until soft and lightly browned. Cool, then squeeze cloves from skins and mash to a paste.

Simmer sauce

In a medium saucepan, combine the canned crushed tomatoes, tomato paste, mashed roasted garlic, dried oregano, dried basil, crushed red pepper flakes (if using), sugar, 1/2 tsp salt and 1/4 tsp black pepper. Bring to a gentle simmer over medium heat, then reduce to low and simmer uncovered for 12–15 minutes, stirring occasionally, until slightly thickened and flavors meld. Taste and adjust salt/pepper.

Vegetable mix

Prepare and sauté vegetables

While the sauce simmers, heat 2 tbsp olive oil in a large skillet over medium-high heat. Add the sliced mushrooms and spread into an even layer; let cook undisturbed 2–3 minutes so they begin to brown. Stir and cook another 2 minutes.

Add the sliced red onion and tri-color pepper strips to the mushrooms. Season with 1 tsp salt and 1/2 tsp black pepper. Sauté, stirring occasionally, for 6–8 minutes until peppers have softened and onions are translucent and slightly caramelized.

Stir in the diced tomatoes and cook 2–3 minutes just to warm through and meld with the other vegetables. Taste and adjust seasoning. If you prefer a saucier result, add 1/2 cup of the warm tomato sauce to the vegetables and toss to combine.

Once vegetables are cooked to desired tenderness, reduce heat to low and pour the prepared crushed & roasted garlic tomato sauce over them. Gently stir to coat and warm together for 1–2 minutes so flavors combine.

Finishing & serve

Turn off heat. Stir in torn fresh basil and drizzle with 1 tsp extra-virgin olive oil. If using, sprinkle grated Parmesan or vegan alternative over the top.

Serve immediately as a pasta topping, over polenta, inside warmed crusty bread, or as a vegetable main alongside grains. Garnish with additional basil leaves. Serves hot.