Gather all ingredients.

Mix together mashed potatoes, potato starch, egg, salt, pepper, garlic powder, and 1 teaspoon of the chives in a medium bowl until combined. The mixture should be slightly sticky but not loose.

Heat 1 tablespoon of the oil in a 10-inch nonstick skillet over medium-high heat until hot and oil is fragrant. Spoon potato mixture into skillet and press it into an even layer to create a potato pancake about 9 inches in diameter.

Reduce heat to medium; cover skillet with a lid or flat cookie sheet and cook, giving skillet a 90-degree turn every 2 to 3 minutes, until golden brown around the edges and top of pancake feels almost dry to the touch, 8 to 9 minutes.

Slide potato pancake onto a large plate. Spray another large plate with nonstick cooking spray and invert the potato pancake onto greased plate.

Add remaining 1 teaspoon oil to skillet and heat over medium. Slide pancake back into skillet and cook, uncovered, until golden brown on the other side, about 5 more minutes.

Slide pancake onto a cutting board and garnish with remaining 1 teaspoon chives.