Season steaks with Jerk spice and set aside until they come to room temperature.
Preheat peanut oil to 350°F in heavy-bottomed pot or deep cast-iron. Place plantains in oil and fry for 8 minutes, or until softened, stirring occasionally to make sure all sides are fried evenly. Be Very Careful, Hot Oil! If you own a table top fryer this is the time to use it!
Remove from oil, and rest on paper towel to absorb excess oil. Transfer fried plantains to a mixing bowl, add garlic and oregano, then mash well with potato masher or large fork.
Preheat oven to 425°F.
Preheat cast-iron skillet over high heat, and add ghee. Once ghee has melted, sear steaks on all sides, for 2 minutes per side. Finish steaks in oven until meat thermometer inserted into thickest part reads 125°F. Let rest 8 minutes before slicing.
Turn heat for cast-iron skillet down to medium. Add ½ of the olive oil and mashed plantains, then sauté for 2 minutes. Add stock and remaining oil and sauté to combine. Season well with salt and pepper.