Marcella Hazan's Spaghetti with Smothered Onions

My favorite onion-featuring dish: they’re sliced thin, cooked until jammy (at least a half hour) in abundant olive oil, with salt and pepper and over pasta. All thanks to the great Marcella Hazan.

Makes: 4 to 6 servings
Time: 1 hour

Ingredients

• 2 tablespoons butter

• 2 tablespoons olive oil

• 1 ½ pounds onions, sliced very thin, about 6 cups

• Salt

• Pepper

• ½ cup dry wh…