To make the homemade hoisin sauce, add all the ingredients to a small bowl, and mix well. Don't worry if the peanut butter doesn't combine perfectly - it'll all melt together in the pan.
Heat a dash of oil in a frying pan, and add all of the sliced mushrooms. Cook over a medium heat for 5 minutes, until soft. Pour over the hoisin sauce, and cook for a further 5 minutes, until the sauce has become thick and glossy.
Serve the hoisin mushrooms in Chinese pancakes, with thin sticks of cucumber and spring onion, and a sprinkling of sesame seeds.