Preheat the oven to 400F. Arrange the bell pepper and zucchini in one layer on a baking sheet. Drizzle with olive oil and sprinkle with salt. Roast the vegetables for 20-30 minutes until browned and soft.

In a large skillet, add the butter, bouillon cube, flour, and garlic over medium-high heat. Cook, stirring as you go, until the bouillon starts to melt into the butter and the flour forms the mixture into a paste, about 5 minutes. Slowly pour in the milk and cream. Let the liquids incorporate with the flour (keep stirring!) and come to a bubble; the sauce will thicken. Add the cheese and stir to melt the cheese into the sauce, saving a little bit for topping the dish.

Add the cooked pasta, the roasted vegetables, and the tomatoes to the sauce. Stir to combine and taste; add salt and pepper to flavor the mac and cheese. Transfer the mixture to a baking dish (9x13 or similar is what I use) and bake for 30 minutes until the dish is browned on top and bubbly.

Serve topped with the scallions and herbs. Enjoy!