Step 1: Preheat your Blackstone griddle to medium-high heat. Add a tablespoon or two of cooking oil (like avocado or canola oil).
Step 2: Add the thinly sliced onions and bell peppers to the griddle. Sauté, stirring occasionally, until softened and slightly caramelized, about 5-7 minutes. Push them to a cooler section of the griddle or into a griddle warming area if your Blackstone has one.
Step 3: Add the thinly sliced steak to the hot section of the griddle. Spread it out in a single layer with your griddle spatula. Season generously with salt, black pepper, and garlic powder. Cook for 2-3 minutes per side, or until browned and cooked through. Break up any larger pieces with your spatula.
Step 4: Once the steak is cooked, mix it together with the sautéed onions and peppers on the griddle. Form into small piles, roughly taco-sized portions.
Step 5: Place a slice of provolone cheese (or a dollop of Cheez Whiz) over each pile of steak and veggies. Immediately cover with a griddle dome or a large lid to help the cheese melt quickly and perfectly.
Step 6: While the cheese is melting, warm your flour tortillas on another section of the griddle. Just a minute or so per side until they're soft and pliable.
Step 7: Once the cheese is gloriously melted, use your griddle spatula to scoop the cheesy steak mixture onto the warm tortillas. Serve immediately!