Heat the oven to 360F (180C).
Place the chopped onion, parsnips and celeriac on a baking tray. Add in the rosemary and drizzle with olive oil. Roast for 30 mins, then cool down and remove the rosemary spring.
Drain and rinse the beans, then place in a large bowl with the roasted vegetables, peanut butter, and nutmeg. Blend with a hand blender until smooth, then season to taste with salt and pepper. If the mixture is too stiff, add 1-2 tbsp. of water. Lastly, add in the eggs and mix well.
Place the mixture in a bread tin lined with baking paper. Bake in the oven at 360F (180C) for 45-55 min. Check with a toothpick for firmness in the middle. Once cooked, cool and chill in the fridge overnight.
Serve with fresh crispy bread and pickles, or with cranberry sauce/jam.
