In an 8-10" frying pan, combine onion, vinegar, 1 tbsp butter, chili, and cumin. Stir over high heat just until sizzling, 2-3 minutes. Add broth and boil until reduced to about 1/2 cup, 3-4 minutes. Scrape mixture into a blender. Whirl until very smooth, then whirl in remaining butter, in chunks. Place cornbread, toasted sides up, on plates and garnish equally with avocado slices. Top with eggs cooked as desired and spoon chili sauce over them. Serve with hot black beans and and crisp bacon.