Because these onions are cooked in so much olive oil and butter, the confit keeps well, covered and stored in the refrigerator, for up to one week. And like most confits, it improves with age. Leftovers can be used on warm open-faced sandwiches or in quiche.
- 1⁄4 cup olive oil
- 2 Tbsp. butter
- 6 medium yellow onions, sliced very thin
- 2 tsp. sugar
- Coarse or kosher salt
- 5 sprigs fresh thyme
- 1 1⁄2 cups full-bodied red wine (e.g., montepulciano or cabernet sauvignon)