Season the steak pieces with salt and pepper. In a large skillet, heat olive oil over medium-high heat. Add the steak and brown on all sides, about 5-7 minutes. Remove from heat and set aside.

In the same skillet, add the diced onion and minced garlic. Sauté until the onion is translucent, about 3-4 minutes.

In the slow cooker, layer half of the sliced potatoes at the bottom. Add half of the browned steak, followed by half of the sautéed onion and garlic mixture. Sprinkle with half of the cheddar cheese. Repeat the layers with the remaining potatoes, steak, onion, garlic, and cheese.

In a bowl, mix together the beef broth, Worcestershire sauce, thyme, and paprika. Pour the mixture evenly over the layered casserole in the slow cooker.

Cover and cook on low for 6-8 hours or on high for 3-4 hours, until the potatoes are tender and the steak is cooked through.

About 15 minutes before serving, stir in the sour cream and let it warm through.

Serve hot, garnished with additional cheddar cheese if desired.