Step 1: Preheat the Oven

Preheat your oven to 375°F (190°C). Proper preheating ensures the casserole bakes evenly.

Step 2: Prepare the Sausage

In a skillet, heat the olive oil over medium heat. Add the sausage and cook until browned, breaking it into small pieces as it cooks. Once cooked, remove the sausage from the skillet and set it aside.

Step 3: Cook the Onions and Garlic

In the same skillet, add the chopped onion and cook until translucent. Add the minced garlic and cook for another minute until fragrant.

Step 4: Combine Ingredients

In a large mixing bowl, combine the sliced potatoes, cooked sausage, onions, garlic, shredded cheddar cheese, salt, pepper, and dried thyme. Mix well to ensure all ingredients are evenly distributed.

Step 5: Prepare the Casserole

Grease a 9×13-inch baking dish with olive oil or non-stick cooking spray. Pour the potato and sausage mixture into the dish, spreading it evenly.

Step 6: Add the Liquids

In a separate bowl, mix the milk and heavy cream. Pour this mixture over the casserole, ensuring it is evenly distributed.

Step 7: Bake the Casserole

Cover the baking dish with aluminum foil and bake in the preheated oven for 45 minutes. Remove the foil and bake for an additional 15 minutes, or until the top is golden and the potatoes are tender.

Step 8: Garnish and Serve

Sprinkle the casserole with fresh chopped parsley before serving. This adds a pop of color and a fresh flavor that complements the richness of the dish.