Prep the steak: Pat the cubes very dry with paper towels. Moisture prevents a good sear.
Toss with salt, pepper, and smoked paprika if using.
Preheat the pan: Set a large cast-iron skillet over medium-high to high heat. Let it get hot for 2–3 minutes. You want it almost smoking.
Add oil: Pour in the avocado oil and swirl to coat.
The oil should shimmer right away.
Sear in batches: Add half the steak in a single layer with space between pieces. Don’t crowd the pan. Sear 1–2 minutes per side until browned.
Transfer to a plate and repeat with the remaining steak.
Make the garlic butter: Reduce heat to medium-low. Add 3 tablespoons of butter to the pan. Once melted, stir in the minced garlic and red pepper flakes.
Cook 20–30 seconds until fragrant. Don’t let the garlic brown.
Finish the bites: Return all steak to the pan, add the remaining 1 tablespoon butter, and toss to coat for 30–60 seconds. Sprinkle with parsley.
Taste and adjust: Add a pinch more salt or pepper if needed.
A quick squeeze of lemon lifts the richness nicely.
Serve hot: Plate immediately so the crust stays crisp. Spoon extra garlic butter from the pan over the top.