For the avocado yogurt: Put the avocados, yogurt, cilantro, chipotle puree, lime juice and some salt and pepper in a blender. Blend until smooth. Cover and refrigerate for at least 30 minutes and up to 4 hours to let the flavors meld.
For the corn cakes: Combine the milk, butter and honey in a small saucepan. Bring to a simmer over low heat and cook until butter has melted. Remove from the heat and let cool for 5 minutes.
Meanwhile, whisk together the corn flour, baking powder, salt and cayenne in a large bowl.
Whisk the egg yolks in a bowl until smooth. Add the cooled milk mixture and mix until smooth, then stir in the corn. Stir the wet mixture into the dry mixture until a batter just comes together. In a clean, dry bowl, beat the 3 egg whites until stiff (they should hold their shape), then fold them completely into the corn mixture.
Heat some butter in a cast-iron skillet over medium heat until almost smoking. Working in batches, make the cakes with 2 tablespoons of batter each, leaving a few inches of space between them as they spread quite a bit. Cook until browned on the bottom and starting to bubble around the edges, about 2 minutes. Flip the corn cakes with a spatula and cook until lightly browned on the reverse side, about 1 minute. Remove to a baking rack to drain.
To assemble: Top each corn cake with a dollop of avocado yogurt, a few pieces of crab and some microgreens.
To make the chipotle puree, just put some chipotle en adobo in a blender or food processor and process until smooth. Extra puree can be refrigerated for 2 weeks, or frozen for 2 months.