Grilled Portobello Burgers - Better Than Bouillon

Ingredients

• 2 tbsp olive oil
• 1 tbsp Better Than Bouillon Seasoned Vegetable Base
• .5 tsp garlic powder
• .5 tsp mustard powder
• 8 large portobello mushrooms, stems trimmed and gills removed
• 4 slices sharp Cheddar cheese
• 4 brioche burger buns, split
• .5 cup aioli
• 1 cup packed arugula
• 4 thick slices beefsteak tomato
• 4 sliced red onion rounds