Preheat oven to 425°F (220°C).

Bake potatoes directly on the upper rack for 40 minutes, or until tender.

Spread fennel wedges in a shallow glass baking dish.

Drizzle with white wine and olive oil.

Season with salt and pepper.

Cover with foil and bake in the bottom third of the oven for 40 minutes, until fennel is tender and golden brown.

Let fennel cool slightly, then chop to measure 3/4 cup.

Cut one-quarter of the cheese into 8 slices.

Dice the remaining cheese and transfer to a medium glass bowl.

Add milk to the bowl.

Microwave at high power for 1 minute, or until the milk is very hot and the cheese is softened.

Halve the warm baked potatoes lengthwise.

Scoop out the potato flesh, leaving a 1/4 inch border of potato inside the skin.

Mash the scooped potato with softened butter.

Pour in the hot milk and cheese mixture, stopping before you reach the unmelted cheese at the bottom of the bowl.

Add the minced garlic.

Mash until smooth and fluffy.

Stir in the chopped roasted fennel and softened cheese.

Season with salt and pepper.

Spoon the potato mixture into the potato skins.

Transfer to a baking sheet.

Top each potato half with a slice of cheese.

Bake in the upper third of the oven for 12 minutes, or until potatoes are hot and cheese is melted.

Sprinkle the chopped fennel fronds over the potatoes.

Serve with roasted fennel wedges.