Cut the tomatoes in half and place them on a foil-lined, rimmed baking sheet. Toss them with two tablespoons of olive oil and a sprinkle of salt and place them in a 425°F oven for 12 to 15 minutes or until the tomatoes have collapsed and are beginning to caramelize. Slice off the tops of the garlic and place the heads on a small sheet of aluminum foil. Drizzle a teaspoon of olive oil on top, add a pinch of salt and then wrap the foil around the garlic to create a sealed pouch. Put the garlic in the oven alongside the tomatoes and roast for 30 minutes.
Bring a large pot of salted water to a boil and cook the elbows for seven minutes or until just shy of al dente. Drain and set aside.
Remove the tomatoes and garlic from the oven when they’re finished cooking and set aside. When the garlic is cool enough to handle, transfer the heads to a cutting board and squeeze out the roasted cloves. Set aside.
In a large saucepot, combine the milk and flour. Constantly whisking, bring the mixture to a boil and cook for about three minutes or until thickened. Remove from the heat. Scrape the roasted garlic cloves into the pot and blend until smooth with an immersion blender. Alternatively, the liquid can be transferred to a food processor or standing blender to mix in the garlic. Place the blended mixture back into the pot. Add the shredded cheese and stir until smooth. If the mixture has cooled too much for the cheese to melt completely, place the pot back on low heat for a few minutes. Stir in the roasted tomatoes and cooked elbow noodles. Spoon the pasta mixture into a 13x9-inch glass or ceramic baking dish coated with non-stick cooking spray. Set aside.
In a small dish, mix together the panko and melted butter. Sprinkle the buttered breadcrumbs over the top of the pasta and bake in a 375°F oven for 20 minutes or until browned and bubbly. Let stand for five minutes and serve.