Over medium-high heat, brown the ground beef with the chili powder, cumin, oregano, onion powder, garlic powder, salt and pepper, stirring to break up the meat into crumbles.
When the beef is browned, add the diced tomatoes, salsa, and olives, and turn down the heat to medium-low. Simmer the filling while you make the topping. Both should finish at about the same time.
For the Mashed Cauliflower Topping
Cook the cauliflower according to package directions. Drain it and put it in a food processor with the butter, cream, ranch powder, and parmesan cheese. Process it until smooth, scraping down the sides as needed. Add salt and white pepper to taste.
Assembly and Baking
Pour the beef mixture into a 9x13 casserole dish and spread it evenly. Using a rubber spoonula, scrape the mashed cauliflower mixture out of the food processor and gently spread it over the filling. Sprinkle the casserole with the cheddar cheese and bake it at 350 for 20-30 minutes, until the cheese is melted but before it begins to brown. Slice into six equal squares to serve.
Macros per serving: 419 calories, 8 grams net carbs, 24 grams protein, 31 grams fat.
Keyword keto, low carb, make ahead, meal prep, Mexican