Grilled Dijon Summer Squash

Ingredients

• 1/4 cup olive oil
• 2 tablespoons red wine vinegar
• 1-1/2 teaspoons minced fresh oregano or 1/2 teaspoon dried oregano
• 1-1/2 teaspoons Dijon mustard
• 1 garlic clove, minced
• 1/4 teaspoon salt
• 1/8 teaspoon pepper
• 2 medium zucchini, cut into 1/2-inch slices
• 2 medium yellow summer squash, cut into 1/2-inch slices
• 1 medium red onions, quartered
• 1 small sweet red pepper, cut into 2-inch pieces
• 1 small sweet yellow pepper, cut into 2-inch pieces
• 6 to 8 whole fresh mushrooms
• 6 cherry tomatoes