For this recipe you can use humble roast chicken leftovers.
You will need 1 liter of chicken stock. In you have roast chicken carcass, place it into the pan to boil.
Boil your chicken stock with 1 sprig of rosemary and 30 g of fresh celery for 15 minutes in case you use roast chicken.
While the stock is cooking, make a base for the mushroom soup. Into the pan add 50 g of finely sliced roast chicken.
Then, take 1 onion, 1 clove of garlic, 1 stick of celery and 1 nice sprig of thyme. Roughly chop onion and celery and add to your chicken. Then add finely chopped garlic and leaves of thyme. When onion gets color, add 150 g of chopped mushrooms into the frying pan. Fry for 5 minutes. As a thickening agent, add 1 tablespoon of plain flour.
Then, sieve 1 liter of your amazing chicken stock into the mushrooms and simmer for 15 minutes.
While your chicken and mushroom soup is simmering, cook delicious crostinis. Take 4 slices of bread and place some of your leftover roast chicken on them. Top with fresh rosemary and cook in the oven for 10 minutes at 180 degrees C.
When cooked, liquidize your soup. Then, add a pinch of salt and pepper.
Serve your chicken and mushroom soup with a teaspoon of double cream per each portion. Place crostinis into each bowl. Finish with a drizzle of olive oil.