Stuffed Portobello Burgers with Caramelised Onions

Serves 4

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.

3 tsp (15 ml) unsalted butter
1 large Spanish onion, sliced into thin rounds
3 tsp (15 ml) coconut palm sugar 
1 tsp (5 ml) balsamic vinegar
2 red capsicum sliced into 4 segments 
8 large portobello mushrooms, stems and gills removed 
4 slices manchego, cheddar or mozzarella cheese
2 cups (500 ml) baby spinach 
4 organic wholegrain buns (optional)

Melt butter in large frying pan 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 barbecue to medium. Lightly brush capsicum slices with oil and cook for 2 minutes per side, or until tender with some grill marks. Remove capsicum from barbecue. Brush mushrooms with oil and season with salt and pepper to taste. Add mushrooms to barbecue, stem sides down, and cook for 5 minutes. Flip mushrooms and cook for another 4 minutes.

Top 4 mushrooms with equal amounts of red capsicum, 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 barbecue for 1 minute or until toasted.

Serve stuffed mushrooms topped with caramelised onions.

Each serving contains: 758 kilojoules; 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: "Vegie Burgers", alive Australia #18, Summer 2013