6 tablespoons extra-virgin olive oil
2 pounds green beans, trimmed
Kosher salt and freshly ground pepper
8 ounces hot Italian sausage, casings removed
1 small red onion, thinly sliced
1 small bulb fennel, halved, cored and very thinly sliced, plus chopped fronds for topping
2 teaspoons fresh thyme
Cook the whole dish up to 4 hours ahead; cover and refrigerate. Reheat in a 300 degrees F oven; top with fennel fronds before serving.