Position a rack in the center of the oven and heat the oven to 375°F.
Arrange the fennel wedges in an overlapping single layer in a 10x15-inch baking dish. Nestle the lemon pieces peel side up among the fennel. Drizzle with the olive oil and 1 Tbs. water, and sprinkle with 1/2 tsp. salt. Cover the baking dish tightly with aluminum foil.
Braise the fennel in the oven until completely tender when pierced with a fork, 1 to 1-1/4 hours. Uncover the dish and continue to braise until the fennel is browned at the edges and there is no liquid left in the pan, about 20 minutes more. Serve warm or at room temperature, garnished with the fronds (if using).
Make Ahead Tips
The fennel will keep in the refrigerator for up to 3 days.
Serve as an appetizer: Layer on toasted bread, along with a few very thin slices of red onion that have been soaked in vinegar and drained. Drizzle with more olive oil.
Add to a sandwich: Use it instead of sliced tomato to top roast beef or turkey in sandwiches.
Stir into pasta: Toss with hot penne, a bit of extra-virgin olive oil, some pasta cooking water, a sprinkle of red pepper flakes, and Parmigiano-Reggiano.
nutrition information (per serving):
Photo: Scott Phillips