1. Prepare the steak:
Start by trimming any excess fat from the steak, then cut it into 1-inch cubes. Pat the pieces dry with paper towels—this helps them brown better and keeps the texture meaty after slow cooking.

2. Sear for flavor (optional but recommended):
In a large skillet, heat the olive oil over medium-high heat. Add the steak cubes in a single layer and sear them for 1–2 minutes per side, just until browned. You don’t need to cook them through—this step is purely for flavor. Remove from the heat and set aside.

3. Prep the potatoes and veggies:
Peel and dice the potatoes into evenly sized chunks. Dice the onion and mince the garlic. Combine the potatoes, onion, and garlic in a large bowl.

4. Season the base:
Sprinkle salt, pepper, paprika, garlic powder, onion powder, and thyme over the potato mixture. Toss until everything is well coated.

5. Layer it up in the crockpot:
In your crockpot (minimum 6-quart size), layer half of the seasoned potatoes and onions. Then add half of the seared steak cubes. Repeat with the remaining potatoes and steak.

6. Pour in the liquids:
In a small bowl, whisk together the beef broth, heavy cream, and sour cream until smooth. Pour this mixture evenly over the steak and potatoes in the crockpot.

7. Cook low and slow:
Cover and cook on LOW for 6–7 hours or HIGH for 3.5–4 hours. The potatoes should be fork-tender and the steak juicy.

8. Cheese it up:
About 15 minutes before serving, sprinkle the cheddar and mozzarella cheeses over the top. Cover again and let the cheese melt completely.

9. Finish with toppings:
Top with  chopped green onions or chives, and a dollop of sour cream if desired.