Bring a large pot of salted water to a boil and preheat the oven to 425 degrees F.
Make the oven-roasted tomatoes. Halve the grape tomatoes and toss with 1 tablespoon olive oil, sea salt, and pepper. Spread tomatoes in a single layer on a parchment-lined baking sheet and roast for 20 minutes, or until the tomatoes are soft and releasing juice.
Prepare the pasta. While the tomatoes are roasting, heat the additional tablespoon of olive oil in a large saute pan. Saute the carrots, onion, and bell pepper until starting to soften. Season with sea salt and pepper. Add in the garlic and cook the vegetable mixture until it starts to get color and is cooked through, about 5-7 minutes. Cook the pasta in the pot of boiling water until al dente.
Prepare the veggie burgers. Cook the veggie burger patties according to package directions (either in a pan or in the oven alongside the tomatoes). Let cool a bit, and then crumble or chop the burgers. Add to the vegetable mixture and toss with the hot, cooked pasta.
Finally, make the sauce. Cook the butter and flour in a saucepan to make a roux; melting the butter until hot and bubbly and whisking in the flour. Continue cooking the roux until light golden brown in color, and to cook out the flour taste, about 3-4 minutes. Slowly whisk in the vegetable broth, constantly stirring to prevent lumps, followed by the milk. Season with sea salt and pepper. Let the sauce very lightly simmer until thickened. Remove from heat and stir in the Dijon mustard and the cheese, little by little, until melted and incorporated.
Pour the sauce over the pasta along with the roasted tomatoes and juices, hot from the oven. Stir to mix everything together and gently stir in the fresh parsley. Serve immediately. Enjoy!