Preheat your oven to 200'C.
Chop your leeks into slices roughly half a centimetre wide. Heat the olive oil in a large casserole dish over a low heat, then add your leeks.
Allow the leeks to cook for ten minutes, until softened, stirring often.
Add the flour and stir in with the leeks so everything forms a paste, then start slowly adding your stock, stirring as you go to make sure you get a smooth consistency.
Once the stock is all added, tip in your beans (including the stock from the jar, don't drain them first) and stir everything together.
Add the nutmeg and thyme, and 30g of the Parmesan, and allow everything to cook for a couple of minutes. Taste and season if needed.
Tip the bean mixture into a baking dish roughly 21cm x 18cm (as long as it all fits don't worry about the dimensions)
Evenly distribute the ground almonds and remaining 20g grated parmesan over the top.
Pop it into the oven for 25 minutes, then remove and allow it to sit for a couple of minutes before serving.
