Spinach and Swiss Chard Pasta

1/2 pound rotini pasta, cooked (save water)
1/4 cup pasta water
1/2 red onion, minced
3 cloves garlic, minced
1 bunch swiss chard, sliced
2 cups baby spinach, sliced
1 1/3 cups tomato pasta sauce
1 1/2 tablespoons heavy cream
1 teaspoon red pepper flakes
Olive oil
Kosher salt

1.  Heat a swirl of olive oil in a pan on medium high heat and add onions and garlic. Cook until onions soften, approx. 3-5 minutes.

2.  Add chard and spinach, along with pasta water and cook down until greens just begin to wilt, approx. 1-2 minutes.

3.  Add pasta sauce, cream and red pepper flakes. Stir well.

4.  Fold in cooked pasta until combined. Salt to taste.