Adapted from Epicurious.com
1 large head cauliflower (about 1 pound total)
4 Tbsp (1/2 stick) unsalted butter
1/4 c all-purpose flour
1/8 tsp fine sea salt
2 c whole milk
10 ounces Cheddar cheese or similar, grated (about 1 1/4 cup)
12- by 8-inch baking dish
Heat oven to 375°F. Arrange steamer over a large pot of boiling water.
Place whole cauliflower on steamer and cook until tender (about 10 mins.) Transfer to a large bowl and let cool. Use your hands to break florets off of central stock. Arange florets in baking dish and set aside.
Heat butter over medium heat in a large saucepan. Reduce heat to low and whisk in flour and salt. Continue to whisk until mixture is golden brown (about 2 mins). Increase heat to medium and poor in milk, whisking constantly. Cook for about 5 minutes. Add 1 c of grated cheese and whisk in until incorporated and melted. Poor cheese sauce into baking pan over florets to cover. Sprinkled with remaining cheese and season with pepper. Bake until cauliflower is golden brown and cheese sauce is bubbly (about 30 mins).