Grease the inside of a 6-quart slow cooker with non-stick cooking spray.

Layer half of the hash browns at the bottom of the slow cooker.

Top with half of the cooked sausage, diced onion, red bell pepper, and shredded cheddar cheese.

Repeat the layers with the remaining hash browns, sausage, onion, bell pepper, and cheese.

In a large bowl, whisk together eggs, milk, dry mustard, garlic powder, salt, and pepper until well combined.

Pour the egg mixture evenly over the layered ingredients in the slow cooker.

Cover and cook on low for 7-8 hours, or until the eggs are set and the edges are lightly browned.

Serve warm directly from the slow cooker.