In a large mixing bowl, add 1 lb of ground turkey. Stir in 1/2 cup of cranberry sauce, 1/4 cup of chopped fresh parsley, 1/2 teaspoon garlic powder, 1/2 teaspoon onion powder, 1/2 teaspoon salt, and 1/4 teaspoon black pepper. Mix until just combined without overworking.
Divide the mixture into 8 equal portions. Shape each into a small, round patty matching the size of your slider buns. Make an indent in the center of each patty with your thumb.
Heat 1 tablespoon olive oil in a nonstick skillet or grill pan over medium heat. Cook patties for 4-5 minutes each side until internal temperature reaches 165°F (74°C). Add cheese slice during last minute if using and cover to melt.
Slice slider buns in half horizontally. Toast lightly if desired.
Assemble sliders by placing each patty on bottom bun half. Add a spoonful of cranberry sauce if desired, then top with bun.
Arrange sliders on a serving platter and garnish with extra parsley if preferred. Serve warm or at room temperature.
