Brown the ground beef in a large skillet over medium-high heat, breaking it apart as it cooks, about 6 minutes, until no pink remains.

Add the onion and cook 2 to 3 minutes, until softened.

Stir in the chili powder, cumin, paprika, cayenne and salt and cook 30 seconds, until fragrant.

Transfer to a slow cooker and add the diced tomatoes, kidney beans and beef broth.

Cover and cook on low for 4 hours, stirring once halfway, until the chili is thick enough that a spoon dragged through it leaves a visible trail that doesn't fill back in right away.

Keep on warm for serving, stirring occasionally to keep the bottom from catching.