2Trim the top from the leeks and place them on a baking tray. Roast for 35-40 minutes, or until charred.
3Heat olive oil in an oven-proof pan. Add flour and garlic, whisk to form a paste. Whisk for a minute to cook the flour.
4Add oat milk gradually, whisking continuously until smooth. Add white wine and rosemary, simmer for 5-6 minutes until thickened. Remove rosemary, stir in nutritional yeast, season.
5Chop each leek in half, scoop out the soft flesh, and roughly chop it. Add the leek flesh and cannellini beans to the sauce. Stir well.
6Transfer the pan to the oven and bake for 15-20 minutes until golden on top. Serve with crusty bread and black pepper.