Cheesy Parsnip Gratin - Pinch Of Nom

Ingredients

• 400 g parsnips (peeled and cut into 2mm thick slices)
• ½ medium onion (peeled and cut into 2mm thick slices)
• 2 garlic cloves (peeled and crushed)
• 1 vegetable stock cube (made up with 400ml boiling water)
• 180 g reduced-fat cream cheese
• 1 tbsp creamed horseradish sauce
• 1 tsp dried thyme
• 30 g Parmesan cheese (finely grated)
• 40 g reduced-fat mature Cheddar cheese (finely grated)
• salt and black pepper (to taste)
• low-calorie cooking spray (for greasing)