In a small bowl mix together mayonnaise, 1 teaspoon minced garlic, and curry powder until smooth.

Heat 2 tablespoons olive oil in a large cast iron skillet over medium-high heat. Once the oil is glistening, add the sweet potatoes to the pan in a single layer. Cook, undisturbed, until golden brown, about 3 minutes. Cook, stirring, another 10-12 minutes, or until fork tender. Transfer to a plate.

Meanwhile, season the steak all over with salt and pepper. Heat the remaining 2 tablespoons of olive oil in the same pan over high heat. Working in batches as needed, add the steak in a single layer, making sure they aren't touching, and cook, undisturbed, until browned and cooked to desired doneness, about 1-2 minutes per side.

Return the sweet potatoes to the pan with the steak. Add the remaining garlic and cook, stirring, 1-2 minutes, or until garlic is fragrant.

Divide between plates, garnish with cilantro if using and serve with curry aioli on the side.