Cut the fennel lengthwise into 6 quarters, discard the green shoots.
Put 2 tbsp olive oil, the bay leaf, thyme and the crushed garlic in a large saucepan and arrange the fennel wedges on top with 100 ml water. Season with salt and pepper.
Place the saucepan on the stove and cook the fennel with the lid on until soft and tender
Prepare the gratin
Peel the potato and cut into 4 to 5 mm slices. Use a brush to grease the bottom and sides of the baking dish with soft butter.
Place the béchamel sauce on the bottom of the baking dish.
Align the cooked potato slices and fennel wedges on the béchamel sauce.
Sprinkle grated parmesan cheese on top.
Bake at 180°C for 25-30 minutes until golden brown on top and serve immediately.
Notes
Étuver is a French culinary word which means cooking vegetables under cover in a small amount of water or fat over a low heat until soft and tender.
Choose fennel that is bright white and has no discoloration or soft spots.