Margarita Beef Skewers

INGREDIENTS

• 1 cup margarita mix
• 1/2 teaspoon salt
• 1 tablespoon white sugar
• 2 cloves garlic, minced
• 1/4 cup vegetable oil
• 1 pound top sirloin steak, cut into 1 1/2-inch cubes
• 8 metal skewers, or bamboo skewers soaked in water for 30 minutes
• 16 mushrooms, stems trimmed
• 1 onion, cut into 1-inch chunks
• 1 large red or green bell pepper, cut into 1 inch pieces