Preheat oven to 400°F and scrub the Russet potato thoroughly.
Pierce the potato several times with a fork and bake for 45-50 minutes until the center is tender.
Heat olive oil in a skillet over medium heat and sauté the diced onions until they become translucent.
Add the ground turkey, sea salt, black pepper, and garlic powder to the skillet, breaking the meat apart and cooking until browned.
Stir the fresh spinach into the turkey mixture and cook for 1-2 minutes until the leaves are completely wilted.
Slice the baked potato in half lengthwise and carefully scoop out the flesh, leaving a 1/4-inch thick shell.
In a small bowl, mash the potato flesh with the Greek yogurt until smooth, then fold in the turkey and spinach mixture.
Stuff the creamy mixture back into the potato shells and top evenly with the sharp cheddar cheese.
Place the boats under the broiler for 2-3 minutes until the cheese is bubbly and golden brown.
Garnish with freshly chopped chives and serve immediately while hot.