Combine potatoes and onion on 9 x 13-inch sheet pan. Stir in 1 Tbsp. olive oil, kosher salt and red pepper flakes until evenly coated. Roast 20 minutes.
Remove from oven. Stir in baby kale, avocado, remaining 1 Tbsp. olive oil and then make four wells. Crack eggs one at a time and carefully place one egg in each well.
Return sheet pan to oven and cook until egg whites are set, about 10 minutes.