Cauliflower "rarebit"

Preheat oven to 350F. Lightly butter a 12x9x2 baking dish. Trim the green leaves from the cauliflower, and cut the head into small florets, removing the core. Bring a pot of slted water to a boil, and add the lemon juice. Add the cauliflower and simmer until just tender, about 10 mins. Drain well and pat dry. Melt the butter in a heavy saucepan over low heat. Whisk in the flour and mustard until it forms a paste. Pour the milk in slowly, whisking until the mixture is smooth. Continue to cook over low heat, whisking, until the sauce is thick, 4-5 mins. Then stir in the grated cheese, Worcestershire, and tabasco, and remove from the heat. Fold in the chives. Arrange the cauliflower in the baking dish so they are standing heads up in an even layer. Pour the sauce evenly over the top, and dust with the bread crumbs. Bake until golden brown, 40-45 mins.