VEGETARIAN BURRITOS

Name: VEGETARIAN BURRITOS
Ingredients: 250 g button mushrooms ((8.8oz)); 1/2 Tbsp olive oil; 3 Tbsp tomato paste; 1 tsp garlic powder; 1 tsp ground coriander; 1 tsp ground cumin; 1 tsp smoked paprika; 2 Tbsp water; 1 tsp brown sugar; 400 g can whole corn kernels, drained ((14oz)); 400 g can black beans, drained ((14oz)); 1 lime wedge; 100 g cos or iceberg lettuce ((3.5oz)); 1 large avocado; 1/4 large red onion; 4-6 jumbo tortillas; 1/2 cup lite sour cream ((125ml)); 1 cup grated cheddar cheese ((100g)); Large handful fresh coriander ((optional))