In a heavy skillet set over medium-high heat, melt the ghee and throw in the ground beef. Cook the meat until it becomes brown and crispy, about 10-12 minutes. Add the black pepper, cumin, coriander, smoked chipotle, onion powder, tomato paste and water. Stir and continue cooking for one or two minutes until the water is completely evaporated. Set aside to cool slightly
Chop the lettuce leaves and divide between 2 bowls. Top with meat mixture, followed by olives, avocado and tomatoes.
Garnish with cashew sour cream and a few slices of lime.