Pasta with Carmelized Onions and Parmesan

All you need for this outrageously tasty dinner is a bag of onions, a couple cloves of garlic, some dried pasta and cheese. Caramelizing sliced onions in a little butter and olive oil turns them sweet and yielding, almost luscious. Pasta water and Parmesan do double duty, adding salt and depth while the creamy sauce forms.

2 Tbsp. extra-virgin olive oil
2 Tbsp. butter
2 lb onions (~ 3 large), thinly sliced
2 cloves garlic, thinly sliced
¼ tsp. crushed red pepper flakes, optional
1½ tsp. sea salt
12 oz linguine or other long pasta
4 oz Parmesan, finely grated (~ 1 cup), divided
½ cup fresh parsley, finely chopped
black pepper, freshly ground

Heat oil and butter in a large heavy pot or Dutch oven over medium until butter is melted. Add onions and garlic and cook, stirring occasionally, until very tender and deeply golden brown, about 30 minutes. (Stop before the onions become dry and shriveled.) Add red pepper flakes (if using) and 1½ tsp. salt. Remove pot from heat.

Meanwhile, cook pasta in a large pot of boiling salted water, stirring occasionally, until al dente. Reserve 1½ cups pasta cooking liquid.

Add pasta and 1 cup pasta cooking liquid to onion mixture and stir to combine. Add a small handful of cheese and stir until melted. Repeat with remaining cheese, adding more pasta cooking liquid as needed to create a glossy sauce that coats the pasta. Stir in parsley (if using).

Divide pasta among bowls. Top with Parmesan, parsley and a few cranks of pepper.

Makes 4 servings.