Cook cabbage and 1 teaspoon salt in 2 cups boiling water 8 minutes. Remove from heat, and drain. Place cabbage in a lightly greased 2-quart baking dish.
Melt butter in a small saucepan over medium-high heat; whisk in flour. Slowly whisk in milk until smooth. Remove from heat, and whisk in remaining 1/4 teaspoon salt and cheese, whisking until cheese is melted. Pour cheese mixture evenly over cabbage. Sprinkle evenly with crushed crackers, if desired.
Bake, uncovered, at 350° for 30 minutes or until bubbly.