Quick and healthy mushroom soup

Name: Quick and healthy mushroom soup
Ingredients: 1/2 cup mushroom sliced; 1/2 capsicum chopped; 1 carrot chopped; 2 sticks spring onion; 2 bulbs of sping onion chopped; 1 tbsp garlic chopped; 1 tbsp ginger chopped; 1 green chilli chopped; 1 tbsp butter; 1/2 tsp black pepper Powder; 3 cup vegetables stock; 6 cups water; to taste Salt; 1 tsp vinegar; 2 tbsp cornflour slurry