Place the ground turkey, pumpkin puree, garlic powder, salt, and black pepper in a mixing bowl. Mix with clean hands until the ingredients are evenly combined.
Divide the mixture into 8 equal portions and shape each into a small, flat patty about 3 inches wide.
Heat the olive oil in a large skillet over medium heat. Add the patties and cook for 4 to 5 minutes on each side until the internal temperature reaches 165°F.
While the patties cook, split the slider buns and place a slice of cheddar cheese on the bottom half of each bun.
Set a cooked patty on each cheese slice. Add a parsley leaf on top of the patty to resemble a pumpkin stem, then close the buns.