Bring a large pot of water to a rolling boil (about 4 cups water for 12 oz pasta). Add 1 tablespoon kosher salt. Add the pasta and cook until just shy of al dente (about 1–2 minutes less than package instructions). Reserve 3/4 cup pasta cooking water, then drain the pasta and set aside.

Roasted Garlic & Tomatoes

Preheat the oven to 400°F (200°C). On a rimmed baking sheet, toss the cherry tomatoes and whole garlic cloves with 2 tablespoons olive oil, 1 teaspoon kosher salt, and 1 teaspoon freshly ground black pepper. Spread into a single layer.

Roast for 18–22 minutes until tomatoes blister and begin to collapse and the garlic is soft and caramelized. Remove from oven and let cool slightly. Squeeze the roasted garlic cloves from their skins and roughly chop or mash them; gently crush a few tomatoes to release juices but keep many halved for texture. Stir in 1 tablespoon aged balsamic vinegar and taste; add a pinch of salt if needed. Set aside.

Garlic Cream Sauce

In a medium saucepan over medium heat, melt 3 tablespoons unsalted butter. Add the 3 minced garlic cloves and cook 45–60 seconds until fragrant but not browned.

Whisk in 3 tablespoons all-purpose flour and cook, stirring constantly, for 1–2 minutes to form a blond roux (don't let it darken).

Gradually whisk in 1.5 cups whole milk and 1/2 cup heavy cream, bringing mixture to a gentle simmer. Continue whisking until the sauce thickens slightly, about 3–5 minutes.

Stir in 1 teaspoon Dijon mustard, 1/2 teaspoon Worcestershire sauce, 3/4 teaspoon sea salt, 1/2 teaspoon freshly ground black pepper, and 1/8 teaspoon grated nutmeg (if using). Taste and adjust seasoning. If sauce is too thick, whisk in up to 1/2 cup reserved pasta water a few tablespoons at a time to reach a creamy consistency.

Remove the sauce from heat and gradually stir in 2 cups grated sharp cheddar, 1 cup grated Fontina (or Gruyère), and 1/2 cup grated Parmesan. Stir until cheeses melt and the sauce is smooth. If the sauce seizes or becomes grainy, return to very low heat and stir in a tablespoon of reserved pasta water at a time until smooth.

Assembly & Bake

Preheat oven to 375°F (190°C) if you plan to bake for a crunchy top. In a large mixing bowl or the pot used for pasta, combine the drained pasta, the garlic cream cheese sauce, and most of the roasted tomatoes and garlic (reserve a few tomatoes for topping). Gently fold until pasta is evenly coated. If the mixture seems thick, add up to 1/4–1/2 cup reserved pasta water to loosen.

Transfer to a shallow 9x9-inch or similar baking dish. Sprinkle the top with the reserved roasted tomatoes, a light sprinkle of Parmesan, and the panko breadcrumb mixture (if using). To make the panko topping: toss 1/2 cup panko with 1 tablespoon melted butter and 1 tablespoon grated Parmesan, then scatter evenly over the pasta.

Bake uncovered for 12–15 minutes until bubbling and the top is golden. For extra browning, broil 1–2 minutes—watch carefully to prevent burning. Remove from oven and let rest 5 minutes before serving.

Finish by drizzling a small amount (about 1 teaspoon per serving) of aged balsamic over the top and sprinkle with 2 tablespoons chopped fresh parsley. Serve warm.