It's always a little fun to use a mortar and pestle in the great outdoors. Especially to make pesto for this awesome sandwich. But there's no shame in bringing a jar of store-bought pesto with you. No shame at all. (You'll need about 1 cup.)

Outdoor Grilled Cheese Sandwich with Pesto and Tomatoes

To make the pesto: In a large mortar and pestle, mash garlic, salt and red pepper flakes into a coarse puree.  

To make the sandwich: Preheat barbecue for high heat (500&#176;F).

Add 1 cup of basil and pound until it is coarsely chopped. Add remaining 1/2 cup of basil and pound until basil forms a coarse puree.

Add pine nuts and pound just to break them up. 

Add cheese and oil and mash until nuts are coarsely ground and mixture is well-blended. 

Toss tomatoes with vinegar and season with salt and black pepper. Set aside and toss occasionally.

Using a large serrated knife, cut ciabatta horizontally in half.

Spread both cut sides with pesto, then top each with Gruyère cheese then Brie cheese. 

For a 2-burner gas grill, turn 1 burner off and place ciabatta halves, cheese-side-up, on grill rack over unlit burner. For a 3-burner gas grill, turn left and right burners off, leaving center burner on. Place ciabatta halves on grill rack over unlit burners. For a charcoal grill, pile charcoal on 1 side of barbecue and place ciabatta halves atop grill rack on opposite side. Placing ciabatta over unlit burners ensures it doesn’t char too much.

Close hood and grill until cheese melts and bread is golden brown, about 10 minutes. Avoid opening hood too often in order to maintain heat inside barbecue.

Transfer sandwich to cutting board. Scatter tomatoes over bottom half of ciabatta; discard juices in bowl. 

Cover with top half of ciabatta, cheese-side-down, and press gently. 

Using serrated knife, cut sandwich into 6 pieces and serve.