Caramelized onions and sour cream make a rich, tangy sauce that clings to pasta. A shelf with only sour cream calls for building around its depth, so onions become the star and this becomes supper in under an hour.

Serves 2. 50 minutes, 15 at the stove.

About 880 calories a serving, 20 g protein, 106 g carbohydrate, 42 g fat. From USDA figures for 83% of the ingredients; amounts are the recipe's.

Cook mode

1. Slice 3 medium onions into half-moons. Heat 3 tablespoons butter in a large skillet over medium-high heat and add the onions with 1/4 teaspoon salt, stirring often.
2. Cook the onions for 25 to 30 minutes, stirring every few minutes, until they are deep golden and caramelized; begin cooking pasta in salted water when you start them.25 min
3. When pasta is al dente, scoop out 1/2 cup pasta water and drain the pasta. Mince 2 cloves garlic and add to the onions, stirring for 30 seconds until fragrant.
4. Remove the skillet from heat and stir in 1 cup sour cream and 1/4 cup pasta water until smooth, then fold in the cooked pasta. Add more pasta water if the sauce is too thick.
5. Season with salt and pepper to taste. Divide between two bowls and top with fresh thyme or chopped chives.

Note Swap the sour cream for crème fraîche if you have it, or use half sour cream and half cream cheese thinned with pasta water. Leftovers keep for three days, loosely covered; add a splash of water when reheating. Serve with a bitter green salad and crusty bread to soak up the sauce.