4 medium-size ripe tomatoes (1-¾ lb. total), cored
1 head garlic, sliced in half crosswise
2 Tbs. plus ⅓ cup extra-virgin olive oil
1-½ oz. (¼ cup) blanched almonds
1-¼ oz. (¼ cup) peeled hazelnuts
1 dried ancho chile, cored, seeded, slit, and opened so it lies fairly flat
1 tsp. kosher salt or sea salt; more to taste
2 to 3 Tbs. red-wine vinegar
2 Tbs. red wine (dry or fruity, but not oaky), if needed
1 slice stale or toasted G-Free white bread, torn, if needed
Heat the oven to 375°F. Put the tomatoes and one half of the garlic head in a baking pan. Drizzle about 1 Tbs. of the olive oil into the cored tomato wells and on top of the garlic half. Roast until the tomatoes and garlic are well caramelized but not burnt, about 90 minutes. From the remaining half head of garlic, coarsely chop 1 Tbs. garlic and put it in a food processor.
While the tomatoes roast, heat about 1 Tbs. of the olive oil in a small sauté pan over medium heat. Toast the almonds and hazelnuts in the pan, shaking the pan or stirring so they don't burn, until golden brown, 5 to 6 minutes. Cool the nuts on a paper towel and then put them in the food processor.
Sear the dried chile in the same small pan over medium-high heat (keep it flat with a spatula or a fork) until a smoke wisp appears, about 10 seconds per side. Soak it in 1 cup hot tap water until soft, about 15 minutes. Drain and put the chile in the food processor.
When the tomatoes and garlic are caramelized, let them cool. Pinch off the tomato skins (discard them) and squeeze out the garlic pulp. Put the tomatoes and garlic pulp in the processor. Add the salt and start the processor, pouring in the remaining ⅓ cup olive oil in a slow, steady stream, as if making mayonnaise. Add the vinegar, pulse to incorporate, and taste; the sauce should have some zing, so add more if needed. Add salt to taste. Process the romesco until it comes together as a sauce but not so much as to lose its coarse, nutty texture. The sauce should be thick and creamy. If it seems too thick, add 1 or 2 Tbs. red wine. If it's too thin, add the G-Free bread, pulsing a few more times.