Lend me your ears!...for some Eva-style Elote - Mind in the Butter

Ingredients

• 3 ears of corn, husks off, stub on (makes it easier to BBQ)
• 1/2 medium red onion, diced
• 1 bunch cilantro, rinsed and roughly chopped
• 1 can black beans, rinsed
• 2 heaping dollops of crema (Mexican sour cream), creme fraiche (French sour cream) or just regular sour cream
• 1 heaping T mayonnaise
• 1/4 cup crumbled cotija cheese or grated Parmesan
• juice of 1 juicey lime
• pinch of cayenne pepper
• 1 ripe avocado