Preheat your oven to 250°F.
Season your tri-tip steak generously with salt, pepper, garlic powder, and paprika.
Heat your vegetable oil in an oven-safe skillet over medium-high heat.
When the oil is hot, sear the tri-tip for 3 minutes on each side until a brown crust forms.
Transfer the skillet to the preheated oven.
Cook the tri tip for 20-30 minutes, or until it reaches an internal temperature of 130°F for medium-rare.
While the tri tip is cooking, melt the butter in a small pan.
Add minced garlic and rosemary to the melted butter and cook until fragrant.
Once the tri tip is done, remove it from the oven and let it rest for 5-10 minutes.
Spoon the garlic-rosemary butter over the steak before slicing and serving.