Peel the onion and garlic and dice finely. Rinse the thyme, shake dry and strip the leaves from the stem.
Rinse and drain the beans well.
Heat 2 tablespoons of olive oil in a saucepan. Sauté the onion and garlic until soft. Add the well-drained beans and the thyme and sauté for 4-5 minutes.
Meanwhile, toast the walnuts in a dry frying pan until fragrant. Remove from the heat, let cool slightly and then chop. Put the beans and walnuts into a mixing bowl and mash coarsely. Add the remaining olive oil and the yogurt and mix well. Stir in the Aleppo pepper and lemon juice and season with salt and pepper. Transfer the spread to a small bowl and serve. If desired, garnish with thyme and chile pepper strips and serve with fresh pumpernickel bread slices.