Begin by bringing a large pot of salted water to a rolling boil. Add 1 lb of Barilla pasta and cook until al dente, approximately 8–10 minutes. Reserve 1 cup of the pasta water before draining.

While the pasta is cooking, slice 7 cups of yellow squash into 1/4-inch rounds, finely dice 1/2 large onion, and mince 4 cloves of garlic.

In a large pan, add 4 tsp of olive oil and heat over medium-high heat. Add the diced onions and sauté for about 1 minute until they soften.

Stir in the sliced yellow squash, minced garlic, 1 1/4 tsp of salt, 3/4 tsp of black pepper, and 1/4 tsp of crushed red pepper flakes. Cook for about 15-20 minutes until the squash is tender and golden brown.

Transfer the cooked squash mixture to a blender, and blend until smooth. Keeping the mixture warm aids blending.

Return the blended mixture to the pan over low heat. Stir in 1 1/4 cups of grated Parmesan cheese until it melts into the sauce.

Gently fold in the drained pasta into the sauce, adding reserved pasta water if the sauce is too thick.

Remove from heat and stir in 1 tbsp of lemon juice. Fold in 1/4 cup of chopped fresh parsley before serving.