Season steak with salt and pepper. Place a pan, preferably a cast iron pan, over medium-high heat. Add 1/2 tablespoon butter and olive oil. Cook steak about 4-6 minutes each side, depending on thickness and keeping in mind it will cook again in the oven.
Let steak rest and then cut into bite-sized pieces. Set aside.
Add remaining butter to pan and cook onion and pepper until soft.
In a large bowl, stir together cream cheese and mayonnaise until smooth.
Stir in garlic powder, provolone cheese and 1 cup of Mozzarella cheese.
Stir in chopped steak and onion and peppers.
Place mixture in a greased baking dish (you can use the cast iron pan you cooked the steak and onion in if it is the right size.)
Bake at 350 degrees for 20 minutes.
Sprinkle remaining mozzarella cheese and green onions on top and bake 5 minutes.
Serve warm with baguette or tortilla chips.