Potato and Cheese Pierogi

Name: Potato and Cheese Pierogi
Prep time: 1 h
Cook time: 30 min
Total time: 1 h 30 min
Cuisine: European
Ingredients: 1 pound potatoes, quartered (red potatoes work well, but use whatever you have on hand!); 2 teaspoons kosher salt; 2 Tablespoons unsalted butter; 2 cloves garlic, minced; 1/2 large yellow onion, diced; salt and pepper to taste; 1 teaspoon dried thyme; 1/2 cup parmesan cheese, shredded; 1/2 cup fontina cheese, shredded; 540g (3 to 4 1/2 cups) all-purpose flour, plus extra for dusting; 3 eggs; 1 tsp. kosher salt; 1/2 cup sour cream; 1/2 cup water (you may not need it all); 4 Tablespoons ghee or clarified butter, for frying; 3 Tablespoons fresh chopped chives; Sour cream or sour cream and chive sauce, for dipping (optional)