To make the dressing, whisk mayonnaise, buttermilk and lemon juice together until smooth. Add remaining ingredients, season. Refrigerate until ready to serve.

Wrap corn cob in a piece of damp paper towel. Place onto a microwave-safe plate. Microwave 3 minutes until almost tender. Set aside to cool. Cut kernels from the cob.

Cook bacon in a medium non-stick frying pan over medium heat until golden. Remove to a bowl, cool. Add the corn and avocado to the bacon, stir gently to combine.

Cut each lettuce wedge in half crossways, arrange board or serving plates. Spoon over the corn mixture. Drizzle with a little dressing. Top with coriander and serve with remaining dressing on the side.