1Preheat oven to 400F. Line a large baking sheet with parchment paper and coat it thinly with olive oil and sprinkle lightly with salt.
2Slice the tomatoes in half through their middles; stems and ends sticking up. Place the tomatoes cut side down on the paper and place in the oven for about 20 minutes, or until they begin to brown and the skins start peeling away from the flesh. Set tomatoes aside to cool slightly.
3Heat the oil, garlic, onions, and minced pepper in a large heavy-bottomed saucepan or Dutch oven over medium heat until the garlic and onions become translucent.
4Peel the tomatoes and add the flesh and juice to the pot, discarding the skins.
5Stir red wine or water into the mixture. Bring to a simmer, then reduce the heat to medium-low and simmer, partially covered, until the sauce thickens and the flavors meld, about 15 minutes. Season with salt and pepper to taste.
6Add tomato paste in small amounts until the sauce thickens to your desired consistency. Simmer to blend the flavors a few minutes longer.
7Serve atop cooked pasta of your choice and finish with a pinch of red pepper flakes for garnish.