In a large skillet, melt butter over medium-high heat. Season steak with salt, pepper, and smoked paprika, then sear for 4-5 minutes until browned.

Layer half of the sliced potatoes, followed by half of the diced onion and garlic, then add the seared steak. Top with remaining potatoes, onion, and garlic.

Pour beef broth and heavy cream over the layers. Season lightly with salt and pepper.

Sprinkle a generous amount of grated cheddar cheese on top.

Cover and cook in the slow cooker on low for 6-8 hours or high for 3-4 hours, until potatoes are fork-tender.

Let the casserole rest, then garnish with parsley or green onions before serving.