Drain can of salmon. Make juice up to 300ml / half pint with water. Mash fish, onion, breadcrumbs, mushrooms and parsley. Fill each cannelloni roll. Lay in a microwave proof dish. Melt butter and stir in flour Cook for 30 seconds on HIGH POWER. Beat fish stock and milk into flour mixture 150ml / quarter pint at a time. Cook for 1 minute between additions. Whisk well. Add pesto and 75g / 3oz of cheese. Pour over cannelloni. Sprinkle with remaining cheese and cover. Cook on MEDIUM POWER for 25 minutes. Stand for 5 minutes. Serve.
Serves 4-6. Approx. 300 kcals per serving