Cardoons baked with Parmigiano and béchamel are a forgotten vegetarian Italian delicacy. This fresh mediterranean dish is a unique, healthy family side celebrating a thistle-like winter vegetable.
Preheat your oven to 375°F. Prepare a large basin of acidulated water (water with lemon juice) to prevent the cardoons from browning after trimming and slicing.
Trim the cardoons, removing tough strings and outer stalks. Cut stalks into 3-inch pieces, placing immediately in acidulated water.
Bring a large pot of salted water to a gentle boil, then add cardoons. Simmer for 30–40 minutes, until tender but not mushy. Drain and pat dry.
In a saucepan over medium heat, melt the butter. Whisk in the flour and cook, stirring constantly, for 2 minutes without browning. Gradually add the milk while whisking, cooking until thickened—then season with salt, pepper, and nutmeg for a smooth béchamel.
Butter a baking dish. Layer half the cardoons, spoon over half the béchamel and sprinkle with half the cheese. Repeat layers, finishing with béchamel and cheese. Bake uncovered for 25–30 minutes, until bubbling and golden brown on top. Let rest 5 minutes before cutting and serving.