Heat oven to 350°F. Spray cookie sheet with cooking spray. Unroll dough; cut loaf crosswise into 10 pieces. On cookie sheet, place rolls, cut sides down, 2 inches apart. Bake 8 to 10 minutes or until light golden brown. Cool 5 minutes.
Cut rolls in half horizontally. Spread mayonnaise evenly on cut sides of roll bottoms; top each with 1 piece of ham and half piece of cheese. Divide spinach evenly among sandwiches. Cover with roll tops.
In small bowl, stir together melted butter and honey mustard. Brush tops of buns with butter mixture.
Place sandwiches on large sheet of foil. Bring up 2 sides of foil so edges meet. Seal edges, making tight 1/2-inch fold; fold again, allowing space for heat circulation. Fold other sides to seal. Place foil packet on cookie sheet.
Bake 10 to 12 minutes or until cheese is melted and sandwiches are hot.