Preheat your oven to 350°F. Season the steaks with kosher salt and freshly ground black pepper.
In a large skillet, heat the canola oil over high heat until it starts smoking. Add the seasoned steaks and cook for 2-3 minutes per side, then set aside and let rest for 5 minutes. Then slice the steaks into thin strips.
In the same skillet, sauté the sliced green bell pepper and white onion over medium heat until they start to soften, about 5 minutes. Add the minced garlic and cook for another minute.
Reduce heat to medium. Add the cream cheese, heavy cream, and Worcestershire sauce to the skillet. Stir until the cream cheese is melted and everything is well combined.
Return the sliced steaks to the skillet, mixing well with the creamy vegetable mixture.
Transfer the mixture into a greased baking dish, spreading it evenly. Sprinkle the shredded cheddar and mozzarella cheese over the top.
Bake in the preheated oven for 15-20 minutes, or until the cheese is bubbly and golden brown.
Let the casserole cool for a few minutes before serving. Enjoy your meal!
Notes
I recommend bringing the steaks to room temperature for at least 30 minutes before searing them. This will help them cook more evenly.
Slice the steak against the grain for the most tender bite.
Bring the cream cheese and cream to room temperature, and add them slowly to the hot casserole. This will prevent curdling.
You can prepare the casserole up to the point of baking and refrigerate it covered for up to 24 hours. You might need to add a few extra minutes to the baking time if you're baking it straight from the refrigerator.
For extra crispy cheese, place the casserole under the broiler for a few minutes at the end of baking.
To store: Wrap the casserole dish or place portions in airtight containers in the refrigerator for up to 3 days.
To freeze: Wrap the casserole with plastic wrap and aluminum foil and freeze for up to 3 months.