Heat one tbsp of olive oil in a saucepan on a medium heat. Sauté the leeks and garlic for 5 minutes until softened. Add in the beans during the last minute to warm through.
Place the leeks, garlic and beans into a food processor, adding the tahini and dairy-free milk. Pulse until you have a roughly blended bean mash.
Toast the slices of granary bread until golden brown.