Step 1

Preheat oven to 350 degrees. Bring 1 inch salted water to a boil in a Dutch oven or large pot. Add cabbage. Cover, and steam, stirring occasionally, until tender, about 5 minutes. Drain, and let cool slightly. Squeeze out excess water using a kitchen towel.

Step 2

Melt butter in a medium saucepan over medium heat. Stir in flour, and cook until bubbling but not browning, 1 to 2 minutes. Slowly whisk in milk. Cook, stirring, until sauce is thick enough to coat the back of a wooden spoon, about 2 minutes. Remove from heat; add 1/4 cup cheese and the lemon zest. Immediately fold cabbage into sauce. Season with salt and pepper.

Step 3

Spoon mixture into a shallow (6-cup) casserole dish. Sprinkle with remaining tablespoon cheese. Bake until bubbling, 30 to 35 minutes. Let stand for 5 minutes before serving.