- 5 Roma tomatoes, halved
- 1/2 cup extra virgin olive oil
- 1 bay leaf
- 2 sprigs fresh thyme
- Salt and freshly ground black pepper
- 8 ounces thinly sliced prosciutto
- 8 slices sourdough bread
- 8 slices fontina cheese, about 8 ounces
- 4 tablespoons unsalted butter, at room temperature
- 4 cups bite-size pieces of lettuce, such as frisee or bibb
Preheat the oven to 300°F.
Place the tomatoes onto a large piece of heavy-duty aluminum foil and drizzle with the olive oil. Sprinkle the bay leaf and thyme over the tomatoes and season generously with salt and pepper. Bring the edges of the foil together and crimp to make an airtight pouch. Bake for 30 to 40 minutes, or until the skin easily peels away from the tomatoes. Remove from the oven and set aside until cool enough to handle. (Reserve olive oil and any accumulated cooking juices.)
Remove and discard the tomato seeds, then cut the tomatoes into thin strips. Place the tomatoes in a small saucepan with 1/4 cup of the reserved olive oil.
Divide the sliced prosciutto evenly among 4 of the slices of bread. Top each sandwich with 2 of the fontina slices, and then place the other slice of bread on top. Spread the outsides of the sandwiches evenly with the butter. Preheat a large skillet over medium heat. Cook the sandwiches, in batches if necessary, until golden brown and crisp on the outside and the cheese is melted and gooey. Set aside briefly while you assemble the salads.
Heat the tomatoes over medium-high heat until just warm. Transfer to a mixing bowl together with the lettuce, season with salt and pepper, and toss gently to combine. Divide the salad evenly among 4 serving plates. Cut the sandwiches in half and arrange around the salad; serve immediately.