Preheat oven to 350°F. Cut bread into 10 slices, cutting to, but not through bottom crust.

In a small bowl, combine butter, dried onion, lemon juice, dry mustard, and seasoned salt. Lightly spread mixture on cut sides of bread. Place cheese between bread slices.

Place bread on 20x12-inch piece of foil. Bring foil up and around bread, leaving only top of bread exposed. Place bread on baking sheet. Bake about 20 minutes or until cheese is melted.