Follow these simple steps to create your delicious Creamy Vegetarian Broccoli Cheddar Pasta. Take your time with each step, especially when making the sauce, to ensure a perfectly smooth and flavorful result.

1. Cook the Pasta: Bring a large pot of salted water to a rolling boil. Add your chosen pasta and cook according to package directions until al dente – tender but still with a slight bite. It’s important not to overcook the pasta at this stage, as it will continue to cook slightly when combined with the sauce.
2. Blanch the Broccoli (Optional but Recommended): About 3-4 minutes before the pasta is done, add the broccoli florets to the boiling pasta water. This method, known as blanching, cooks the broccoli perfectly, retaining its vibrant green color and tender-crisp texture. If you prefer softer broccoli, you can add it a minute or two earlier.
3. Reserve Pasta Water and Drain: Once the pasta is al dente and the broccoli is tender-crisp, reserve about 1 cup of the starchy pasta water. This water is gold! It can be used later to adjust the consistency of your cheese sauce if it becomes too thick. Drain the pasta and broccoli mixture through a colander and set aside. Rinsing is not necessary.
4. Sauté Aromatics: While the pasta is cooking, or just after, melt the unsalted butter in a large skillet, Dutch oven, or heavy-bottomed pot over medium heat. Once the butter is melted and foamy, add the finely chopped yellow onion. Sauté for about 5-7 minutes, stirring occasionally, until the onion is softened, translucent, and fragrant. Be careful not to brown it, as this can introduce a bitter taste. Add the minced garlic and smoked paprika (if using) and cook for another minute, stirring constantly, until the garlic is fragrant. This step blooms the spices and infuses the oil with flavor.
5. Make the Roux: Sprinkle the all-purpose flour over the sautéed onions and garlic. Whisk or stir constantly for 1-2 minutes to cook out the raw flour taste. This mixture of butter, aromatics, and flour is called a roux, and it’s the foundation for a thick and creamy sauce. It should look like a thick paste.
6. Build the Sauce Base: Gradually whisk in the vegetable broth, a little at a time, ensuring each addition is fully incorporated before adding more. This slow addition helps prevent lumps from forming. Once all the broth is whisked in and the mixture is smooth, gradually whisk in the milk.
7. Simmer and Thicken: Bring the sauce to a gentle simmer, stirring frequently to prevent it from scorching on the bottom. Continue to cook and stir for about 3-5 minutes, or until the sauce has thickened enough to coat the back of a spoon. You’ll notice it becoming visibly more viscous.
8. Add Flavor Enhancers: Stir in the Dijon mustard. Taste the sauce at this point and season with salt and freshly ground black pepper to your liking. Remember that the cheese will also add saltiness, so be conservative initially.
9. Melt the Cheese: Reduce the heat to low. This is a crucial step to prevent the cheese sauce from becoming grainy or separating. Add the freshly grated sharp cheddar cheese to the sauce, a handful at a time, stirring gently and constantly until each addition is fully melted and incorporated before adding the next. If using, add the cubed cream cheese at this stage as well, stirring until it’s completely melted and the sauce is smooth and velvety. Avoid letting the sauce boil after adding the cheese.
10. Combine and Serve: Add the cooked pasta and broccoli mixture to the skillet with the cheese sauce. Gently stir everything together until the pasta and broccoli are evenly coated in the glorious, creamy cheddar sauce. If the sauce seems too thick, add a splash or two of the reserved pasta water, a little at a time, until it reaches your desired consistency. The starchy pasta water not only thins the sauce but also helps it cling to the pasta better.
11. Garnish and Enjoy: Serve the Creamy Vegetarian Broccoli Cheddar Pasta immediately, garnished with fresh chopped parsley, if desired. A little extra freshly ground black pepper on top also adds a nice touch. Enjoy the comforting, cheesy goodness!