1. Stir together first 3 ingredients.
2. Spread butter mixture evenly on cut sides of top bun halves; spread mayonnaise evenly on cut sides of bottom bun halves. Place 3/4 cup Roasted Summer Vegetables evenly on each bottom bun half; top each with 1 provolone cheese slice and remaining bun halves. Wrap each sandwich lightly in aluminum foil, and place on a baking sheet.
3. Bake at 400° for 10 to 12 minutes or until cheese melts.
Note: For testing purposes only, we used Publix Deli French Hamburger Buns.