This is one of those dishes you try on a whim, instantly fall in love, and can't wait to find an excuse to make it again.
Adapted from Epicurious
4 tablespoons (3/4 stick) butter, divided
1/2 pound shallots, thinly sliced*
Coarse kosher salt
freshly cracked pepper
2 tablespoons red wine vinegar
2 teaspoons sugar
1 1/2 pounds brussels sprouts, trimmed and thinly sliced
3 tablespoons extra-virgin olive oil
1 cup water
2-3 strips of bacon or pancetta, chopped
Melt half of the butter in pan over medium heat, add shallots (if using bacon or pancetta add now but omit butter) and season with salt and pepper. Saute until soft and golden, about 10 minutes. Add vinegar and sugar and cook shallots until glazed.
Remove shallots from heat and set aside.
Add oil and sprouts to pan and season with salt and pepper. Saute until beginning to brown, then add water and remaining butter. Saute until most of the water is evaporated. Sprouts should be tender but still bright green. Add shallots and stir to combine, and season with salt and pepper.