1. In a large bowl, mash together all guacamole ingredients until fully combined. Set aside and over tightly until serving.
2. In a medium frying pan, heat 2 tablespoons of butter, until melted.
3. Add in onions and fry for 4-5 minutes until golden brown.
4. Season with cumin, chili powder, garlic powder, kosher salt, and freshly cracked pepper.
5. Cook for an additional 2-3 minutes.
6. Transfer onions to a bowl and wipe out the pan.
7. Add a small slab of butter to the pan and place in a tortilla.
8. Top with cheese, a spoonful of onion, more cheese, and then another tortilla.
9. Cook for 2-3 minutes per side, until browned.
10. Repeat with the rest of the tortillas, cheese, and onions. Serve with guacamole.