How to Make It
Preheat the oven to 250°. Arrange the tomatoes on a large rimmed baking sheet, cut side down. Brush with olive oil and season with salt and pepper. Bake for about 1 1/2 hours, or until the skins shrivel. Let the tomatoes cool slightly, then peel and seed them over the baking sheet and transfer them to a bowl. Scrape the seeds, skins and any juices from the baking sheet into a fine sieve set over the bowl and press to extract as much juice as possible.
Heat the 2 tablespoons of olive oil in a large saucepan. Add the onion and cook over moderately low heat, stirring occasionally, until softened, about 10 minutes. Stir in the ham, roasted tomatoes and their juices and the stock and bring to a boil. Reduce the heat and simmer the soup for 45 minutes.
Preheat the oven to 325°. In a medium skillet, melt the butter in the olive oil. Add the garlic and cook over low heat, stirring, until fragrant, about 2 minutes. Stir in the minced herbs and cook for 30 seconds. Scrape the mixture into a medium bowl, add the bread cubes and a generous pinch of salt and pepper and toss thoroughly. Spread the bread cubes on a large rimmed baking sheet in a single layer and bake for 20 minutes, stirring occasionally, until golden.
Coarsely mash the tomatoes in the soup and season with salt and pepper. Put the croutons in shallow bowls, ladle the soup on top and serve piping hot.