Gratin de Cardons
- Cut off bases, and discard tough outer stems.
- Trim remaining stems, removing strings, leaves and prickles.
- Quarter hearts lengthwise.
- Wash and slice stems into 3- to 4-inch pieces, and rub with lemon to prevent discoloration.
- Combine ingredients in stockpot over medium heat, and bring to a boil.
- Place cardoon stems and hearts in pan with crusty stale bread to help remove bitterness of cardoons.
- Cook 15 to 20 minutes, remove from heat and cool.
- When cool enough to handle, lift edge of each piece with paring knife, and peel off skin.
- Trim away toughest fibrous strings down to tender stems.
- Soak trimmed cardoon pieces in water to cover with several tablespoons vinegar until ready to use.
- Melt butter in heavy saucepan over low heat.
- Add onion, and cook until pale golden.
- Add flour, and stir well, about 1 minute.
- Slowly add 1 cup milk, stirring constantly, and continue cooking 35 minutes more.
- When sauce thickens, slowly add more milk until all milk is used up.
- Add clove, sugar and bouquet garni.
- Continue to cook 1½ hours, stirring and scraping occasionally.
- Whisk sauce, and strain, removing bouquet garni and clove.
- Add heavy cream, if desired, and a pinch nutmeg and salt to taste.
- Preheat oven to 450°F.
- Lightly butter ovenproof baking dish.
- Place cardoons in baking dish.
- Add béchamel to cover evenly.
- Sprinkle uniformly with freshly grated Parmesan cheese and small pieces of butter for topping.
- Bake 5 to 10 minutes, or until golden.
- Remove from oven, and serve.