1. Heat the olive oil in a large skillet or Dutch oven over medium heat. Add the chopped yellow onion and cook for 3-5 minutes until it softens and becomes translucent. Stir in the minced garlic and cook for another minute until fragrant, being careful not to burn it.

2. Stir in the broccoli florets and vegetable broth. Bring the mixture to a gentle boil, then reduce the heat to medium-low and let it simmer for about 5 minutes, allowing the broccoli to start tenderizing.

3. Add the uncooked pasta to the skillet, stirring to ensure it’s submerged in the broth. Cover the skillet and continue to cook for 10-12 minutes, or according to package directions, stirring occasionally to prevent sticking. The pasta should be al dente, and most of the liquid should be absorbed.

4. Pour in the milk and heavy cream. Stir in the Italian seasoning, salt, and black pepper. Continue to cook, uncovered, for another 2-3 minutes, allowing the sauce to gently thicken.

5. Remove the skillet from the heat. Stir in the shredded cheddar cheese and grated Parmesan cheese until completely melted and smooth. The residual heat from the pasta and sauce will melt the cheese beautifully, creating a rich, luscious sauce.

6. Let the skillet sit for 2-3 minutes before serving. This allows the sauce to further thicken and cling perfectly to the pasta and broccoli. Serve hot and enjoy!