Sausage, Spinach and Ricotta Lasagne - Pinch Of Nom

Ingredients

• 6 dried 'no-precook' lasagne sheets
• 1 medium onion, peeled and finely chopped
• 4 reduced-fat pork sausages, skinned
• 250 g baby spinach leaves
• 250 g ricotta cheese
• 15 g Parmesan cheese (finely grated)
• 1 tsp garlic granules
• salt and freshly ground black pepper (to taste)
• low-calorie cooking spray
• 500 g passata
• ½ tsp garlic granules
• ½ tsp dried Italian herbs
• 40 g reduced-fat Cheddar cheese (finely grated)