This is a Nancy Silverton recipe. (creator/founder of La Brea bakery)
The recipe is pretty simple and has the onions fall-apart tender. The fennel seeds really give the crispy topping a punch in flavor.
Serves 4 to 6
3 medium onions, peeled and halved lengthwise, root ends left intact
2 tbsp extra virgin olive oil, plus more for brushing
Kosher salt
1/2 cup chicken stock
6 bay leaves, preferably fresh
1 tsp fennel seeds
1/4 cup panko breadcrumbs
1 1/2 tsp minced sage
Preheat the oven to 425 F
Brush the onion halves with olive oil, season with salt and arrange cut side down in an ovenproof medium skillet. Add the chicken stock and scatter the bay leaves around the onions.
Cover tightly with foil and bake for about 1 1/2 hurs, until the onions are very tender
Meanwhile, in a small skillet, toast the fennel seeds over a moderate heat until fragrant, about 3 minutes. Transfer to a work surface and let cool, then coarsely crush the seeds. Transfer them to a small bowl, add the panko crumbs, sage and 2 tbsp of olive oil and toss well. Season with salt to taste.
Carefully turn the onions cut side up in the skillet. Spoon the fennel breadcrumbs on top and bake for about 15 to 20 mins longer, until the crumbs are lightly browned and crisp. Discard the bayleaves and serve the onions hot or warm.
Make ahead
The baked onions can be refrigerated overnight. Let them return to room temperature and top with the breadcrumbs before baking.