Mushroom Spinach Tortellini

I really love tortellini, it's on of those pastas that I could eat every day. When I saw this recipe I knew it would be something Gray and I would enjoy.  It was a great deal, I slightly adapted it from The Food Charlatan.

1 (20 oz) package cheese tortellini
3 tbsp olive oil
1 cup chopped onion
8 oz fresh sliced mushrooms
1 tsp salt
1/2 tsp pepper
2 cloves garlic (minced)
2 (14.5 ounce) can diced tomatoes with basil and garlic
3 tbsp flour
3 cups half and half
1/2 cup grated Parmesan cheese
2 cups fresh spinach

Boil the pasta according to the directions.  While the pasta is boiling heat the olive oil over medium heat and saute the onions and mushrooms for 4 to 6 minutes. Season with salt and pepper. Add in the garlic and stir, cook for 30 seconds.  Stir in the diced tomatoes and bring a boil, reduce heat to a simmer.  In a small mixing bowl whisk the flour into the half and half.  Add the half and half mixture to the tomatoes and stir in the parmesan cheese. Heat through then reduce to a simmer. Cook for 2 to 5 minutes then add the tortellini and spinach.  Serve once the spinach has wilted.