Spray a frying pan with low-calorie cooking spray and set on a low-medium heat. Cook the bacon, leeks and garlic for 4-5 minutes until the leeks are softening and bacon browned. Slice the bacon and leave to one side with the leeks to cool.
Preheat the oven to 170°C.
Break the eggs into a large bowl and whisk. Add the double cream alternative, quark, Dijon mustard and garlic granules. Continue to whisk until fully combined. Season well with salt and pepper.
Stir through the cheddar cheese, bacon and leeks. Pour the egg mixture into a 24cm flan dish. Sprinkle over the Parmesan cheese.
Place the dish onto a baking tray and pop into the oven for 25-30 minutes, until the quiche is golden brown. The quiche should be set around the edge with a very slight wobble in the centre. The heat from the quiche will finish cooking the centre, so that it has a light creamy quiche texture when slicing.