Step 1

Brown the beef with the onions (can be done a day or two ahead): Heat the olive oil in a large skillet or sauté pan over medium-high heat. Add beef and onions and cook 2 to 3 minutes, until the ground beef is browned but not completely cooked and the onions are starting to look soft around the edges. Use your spatula to break up the ground beef into smaller pieces as it cooks. Remove from heat and use immediately, or refrigerate for a day or two until needed.

Step 2

Combine and cook: Combine the browned beef, onions and the remaining soup ingredients in a slow cooker and stir. Cover and cook on low for 6 to 7 hours. It's fine if the soup cooks a little longer or the slow cooker switches to the "warm" setting.

Step 3

Serve the soup: Serve soup in bowls and top with crushed tortilla chips, sour cream, cilantro, red onion and lime juice.This soup will keep refrigerated for 1 week or frozen for up to 3 months.