Pre-heat the oven to 350. Lightly mist a 9x13 baking dish with cooking spray and set aside.

Cook pasta in salted water according to package instructions. Drain and set aside.

While the water is boiling for step one, melt one tablespoon of the light butter in a medium saucepan over medium-low heat. Add the onion, garlic and red pepper flakes and cook for about 5 minutes until softened. Add the canned tomatoes, vegetable broth, basil and thyme and raise heat to bring to a boil. Reduce heat and simmer uncovered for 15 minutes.

While the tomatoes are simmering, melt the remaining 2 tablespoons of light butter in another saucepan. Add the flour to the butter and stir to combine. Add the milk a little at a time and whisk the flour mixture into the milk until smooth. Add the mustard powder and salt and stir to combine. Add 4 ounces of the shredded cheese (set aside 2 ounces for topping) to the milk mixture and whisk together until smooth. Make sure heat is on the lowest setting and warm cheese sauce for about 5 minutes to thicken.

When the tomato mixture is done simmering, pour it into a blender (or use an immersion blender – one of my favorite tools!) and blend until smooth. Add the tomato mixture to the cheese sauce and stir to combine. Mix in the cooked pasta until well coated. Pour the pasta mixture into the reserved baking dish and sprinkle the reserved cheese over the top. Bake for 20 minutes until cooked through and bubbly.