Preheat the oven to 325°F.

Place the potatoes in a small saucepan and cover with water. Add 1 teaspoon of salt. Bring to a boil and cook until the potatoes are tender, 10 to 12 minutes. Drain and set aside to cool.

In a blender, combine the eggs, butter, cottage cheese, onion powder, vinegar, hot sauce, mustard, and the remaining 1/4 teaspoon of salt. Blend on high until well combined, about 20 seconds.

In a small bowl, combine the Gruyère, Monterey Jack, and white cheddar cheeses.

Divide the cooled potatoes, cheese mixture, and chopped spinach among the cups in a greased muffin pan. Add the egg mixture and top each cup with cheddar cheese and chives.