In a blender, combine the half-and-half, milk, egg, egg yolk, cream cheese, avocados, salt and pepper. Blend until smooth. Pour the mixture into 4 (4-ounce) ramekins.
Arrange the ramekins in a glass baking dish, and add enough hot water to come halfway up the sides. Cover the baking dish with foil. Bake until the custard is set, about 1 hour. Remove the flans from the oven. Cool to room temperature then refrigerate for 1 hour. Bring the flans to room temperature for 30 minutes before serving. Top with corn relish and serve.
In a small bowl, combine the corn, cilantro, red onion, and lime juice. Season with salt and pepper, to taste.