Step 1

Position a rack in the center of the oven and preheat to 475 degrees F.

Step 2

Pick 2 tablespoons of the tender green fronds from the tops of the fennel bulbs and set aside. Cut the remaining top and bottom from each fennel bulb, then cut the bulb in half lengthwise through the core. Use the tip of the knife to cut an upside-down "V" on the bottom of each bulb to remove most of the core, leaving just enough so the bulb stays intact. Cut each half through the core into wedges, about 1/4 inch thick.

Step 3

Add the fennel bulb, thyme, garlic, olive oil, red pepper flakes and 3/4 teaspoon salt to a large bowl and toss until evenly coated. Transfer to a rimmed baking sheet.

Step 4

Roast in the oven until the fennel is very tender and lightly browned in spots, 30 to 35 minutes. Transfer to a serving platter, top with the reserved fennel fronds and serve with the lemon wedges.