Brown the beef in a skillet over medium-high heat, breaking the beef up with your spoon as you go along. Once the meat has browned, drain most of the fat (I like to leave a bit in for flavor), and add it to your Crockpot.
Add the remaining ingredients to your slow cooker and stir well.
Close the lid and cook on low for 6-8 hours or high for 3-4 hours.
Prior to serving, prepare your toppings. Give the soup a taste and season with salt & pepper if needed. Top the soup to taste and eat right away.
Notes
Anything from 1-2 pounds of ground beef will work - I don't worry too much about the exact quantity.
If you're sensitive to salt, use low-sodium beef broth.
You can use regular diced tomatoes, but fire-roasted ones have more flavor.
If you want a more mild soup, don't add the cayenne pepper.