Turn on an oven to preheat to 375 F (190 C) and line a sheet tray with parchment paper. Shred parmesan cheese from a block, then divide the cheese into ¼-cup portions. Spread each portion out into a thin circle of cheese on your lined sheet tray.
Bake the cheese circles anywhere from 8-15 minutes in your oven. You’ll need to watch the cheese as it melts, bubbles then hardens in place. Once the cheese is baked, remove the tray from the oven to cool. The parmesan circles should naturally release from the paper.
Make the scrambled eggs for the tostadas by whisking together eggs, heavy cream, salt, pepper, cumin, paprika, cayenne, and onion powder. You can omit the cayenne pepper if you wish. Cook the egg mixture over medium-low heat on your stove while you scramble it.
Slice avocado into thin slices. Cook bacon strips until they’re crispy, and you can cut them to size if needed. Assemble each tostada with a parmesan circle, a pile of scrambled eggs, about ½-ounce avocado slices, and 1-2 pieces of bacon.