This tastes rich but isn't - no cream in it. Instead, it starts with a roux and you add milk and pureed spinach for a rich, creamy, green sauce. Add sausage, ham, chicken, or beans for more of a main dish. Feel free to substitute other greens for the spinach.
1 lb dry pasta
3 Tbsp olive oil (1 + 2)
8-10 cloves garlic, minced
1/2 lb spinach, stemmed and rinsed
2 Tbsp all purpose flour
3/4 cup milk (whole is good, but use what you like)
1/2 tsp lemon juice
Salt and pepper to taste
Cook the pasta in a large pot of salted water. Prepare the sauce while you bring the water to a boil and cook the pasta.
Heat 1 Tbsp olive oil in a large skillet. Add the garlic and saute for about 3 minutes over medium-high heat. Add the spinach and saute, stirring frequently, until it is wilted but not mushy. Remove from heat. Puree the garlic-spinach mixture until very smooth, then set aside.
In a medium saucepan, heat the remaining 2 Tbsp of olive oil over medium heat. Reduce heat to low-medium and whisk in the flour. Continue whisking until smooth. Slowly pour in the milk, whisking constantly to get rid of the lumps. Continue to whisk as it thickens to a creamy consistency. Turn off the heat, then whisk in the spinach mixture until thoroughly combined. Stir in the lemon juice and add salt and pepper to taste.
When the pasta is cooked, drain and toss with a little olive oil, then add the sauce and stir to coat. Add cooked meat or beans at this point, if using.