Mushroom and Spinach Lasagne - Pinch Of Nom

Ingredients

• 6 sheets no precook wholewheat lasagne sheets
• 1 medium onion (chopped)
• 1 medium red pepper (diced)
• 1 medium egg (beaten)
• 430 g medium flat mushrooms (sliced)
• 400 g tinned chopped tomatoes (drained)
• 460 g ricotta cheese
• 260 g fresh spinach leaves (rinsed and drained)
• 1 clove garlic (crushed)
• 25 g Parmesan cheese (grated)
• 40 g 30% less fat Cheddar cheese (grated)
• 4 tbsp skimmed milk
• 2 tbsp Henderson's Relish
• 1 tbsp tomato puree
• 1 tsp dried oregano
• low calorie cooking spray
• salt and pepper (to taste)