Ingredients

• 1 tablespoon olive oil
• 2 large onion(s), thinly sliced
• 1 clove garlic, crushed
• 1 sprig fresh rosemary, finely chopped
• 100 ml water
• 2 teaspoon vinegar, balsamic
• 2 teaspoon muscavado sugar, dark or light
• 1 pinch salt, and black pepper, freshly ground
• 5 spray low-fat cooking spray
• 250 g mushrooms, closed cup, sliced
• 1 tablespoon butter
• 3 level tablespoon flour, plain
• 600 ml skimmed milk
• 135 g lasagne sheet, (9 sheets)
• 40 g parmesan cheese, finely grated
• 1/8 teaspoon nutmeg, ground, optional

Instructions

• Heat olive oil in a large non-stick frying pan over a high heat. Add onions and cook, stirring occasionally for 6-8 minutes until golden brown. Add garlic and rosemary and cook for 1 minute. Stir in water, balsamic vinegar and sugar. Cook until water evaporates �?about 1-2 minutes. Tip into a large bowl, season with salt and pepper and set aside.
  
  
• Coat same frying pan with low fat cooking spray. Place over medium-high heat and add mushrooms. Cook for about 2 minutes until browned, then add to onions, stirring to mix.
  
  
• Preheat oven to Gas Mark 4/180°C/fan oven 160°C/ 350°F.
  
  
• To make sauce put butter, flour and milk into a non-stick saucepan, all at once. Heat, stirring constantly with a small whisk until the sauce boils and thickens. Add half the cheese. Season and add nutmeg, if using.
  
  
• To assemble, spread a thin layer of sauce over the base of a baking dish measuring about 18 x 28cm. Place 3 lasagne sheets on top. Spread with sauce and half the onion mixture. Lay 3 more lasagne sheets on top. Repeat with sauce, onion mixture, final 3 lasagne sheets and remaining sauce. Sprinkle the rest of the cheese evenly over the