Sauté Garlic: In a large pot or Dutch oven, heat the olive oil over medium heat. Add the minced garlic and cook for 30-60 seconds until fragrant, being careful not to burn it.
Boil & Cook Pasta: Pour in the vegetable broth and water, add the salt, and bring to a rolling boil. Add the uncooked pasta, stir once, and cook for 10-12 minutes (or according to package directions for al dente), stirring every few minutes to prevent sticking. Most of the liquid should be absorbed by the end.
Make the Sauce: Turn the heat down to low. Add the ricotta cheese, Parmesan cheese, and lemon juice to the pot with the pasta and the remaining starchy liquid. Stir vigorously and continuously until the cheeses melt into a smooth, creamy sauce that coats the pasta.
Add Spinach: Remove the pot from the heat. Add the fresh spinach and stir until it is just wilted from the residual heat.
Serve: Taste and season with additional salt and plenty of black pepper as needed. Serve immediately in bowls, garnished with fresh lemon zest, more Parmesan, and fresh basil if desired.