Stuffed Portobello Burgers with Caramelized Onions

These giants of the fungi world have a meaty bite that will appease even the most carnivorous burger lover. The stuffed mushrooms are wonderful as a bunless knife and fork affair or try serving between slices of toasted focaccia or ciabatta.

1 Tbsp (15 mL) unsalted butter
1 large Spanish onion, sliced into thin rounds
1 Tbsp (15 mL) coconut palm sugar
1 tsp (5 mL) balsamic vinegar
Grapeseed oil for grilling
2 red bell peppers, sliced into 4 segments
8 large portobello mushrooms, stems and gills removed
Salt and pepper to taste
4 slices manchego, white cheddar, or mozzarella cheese
2 cups (500 mL) baby spinach
4 whole grain buns (optional)

Melt butter in large skillet over medium heat. Add onions and cook until translucent, about 5 minutes. Stir in sugar and balsamic vinegar. Reduce heat to medium-low, cover pan, and cook for 30 minutes, stirring occasionally.

Preheat grill to medium. Lightly brush red pepper slices with oil and grill for 2 minutes per side, or until tender with some grill marks. Remove red pepper from grill. Brush mushrooms with oil and season with salt and pepper to taste. Add mushrooms to grill, stem sides down, and cook for 5 minutes. Flip mushrooms and cook for another 4 minutes.

Top 4 mushrooms with equal amounts of red peppers, cheese, and spinach. Cover each with a remaining mushroom, stem side down so that the stem sides are facing each other. Cook for 1 minute or until cheese has melted. If using buns, heat them on the grill for 1 minute, or until toasted.

Serve stuffed mushrooms topped with caramelized onions.

Serves 4.

Each serving contains: 181 calories; 10 g protein; 8 g total fat (5 g sat. fat, 0 g trans fat); 20 g total carbohydrates (11 g sugars, 5 g fibre); 159 mg sodium

source: "Veggie Burgers", alive #370, August 2013