Preheat oven to 180°C.
Heat oil in a frying pan and sauté the onion until soft.
Add the mushroom variants and fry for 5 minutes.
Stir in the red pepper pesto and pour into a suitable ovenproof dish.
Empty KNORR Black Pepper Sauce sachet contents into a jug.
Fill up to the 250 ml mark with boiling water.
Stir with a fork for 1 minute until thick and smooth.
Pour over the mushrooms and sprinkle with parsley, cheese and breadcrumbs.
Place in a preheated oven for 20 min.
Serve on toasted bagels.