Wash the lettuce thoroughly in plenty of water, tear into bite-sized pieces and spin dry. Clean and wash the chanterelles (but only rinse them briefly under cold running water so that they cannot soak up water) and let them drain.
Cut the bacon into very fine strips, leave in a pan (without adding any fat), remove the greaves from the pan and drain on kitchen paper.
Melt the butter or margarine in the bacon fat, add the mushrooms and fry for about 1 minute, stirring constantly, but they should not draw any liquid, then they will stay crisp. Mix the balsamic vinegar, oil, salt, pepper and the finely diced shallot into a dressing and fold into the oak leaf salad. Serve the salad sprinkled with the still warm chanterelles and the bacon cracklings.