3 medium bulbs fennel, fronds reserved
4 cups milk
4 tbsp. unsalted butter
1 tsp. fennel seeds, crushed
Kosher salt and freshly ground black pepper, to taste
1 cup freshly grated Parmesan
Heat oven to 475. Remove tough outer layer of fennel. Halve bulbs lengthwise and cut into 1?2? wedges. Combine fennel, milk, and 2 tbsp. butter in a 4-qt. saucepan over medium-high heat and cook, stirring occasionally, until fennel is just tender, 30?45 minutes. Add fennel seeds and season with salt and pepper.
Using a slotted spoon, transfer fennel to a 2-quart oval baking dish; pour 1 cup of the milk mixture over fennel. Sprinkle with Parmesan, dot with remaining butter, and bake until golden brown and bubbly, about 20 minutes. Serve fennel garnished with some of the fronds.