Make the stone ground mustard aioli by mixing together the mayonnaise with stone ground mustard, and lemon juice. Season with salt and pepper.
Heat 2 tablespoon olive oil in a saute pan over medium heat. Add the red onion and saute until the onions are softened and translucent, about 5 minutes. Add the kale and toss to combine. Cook until the kale begins to soften, about 3-4 minutes. Add the garlic and cook for another minute.
Reduce the heat to low and add the sherry to the pan. Simmer the kale until it is tender and almost all of the liquid has evaporated. Add the heavy cream and simmer for another 4-5 minutes. Season with salt and pepper and remove from heat.
Meanwhile, prepare the remaining ingredients. Toast 4 slices of bread and fry 4 eggs until the desired degree of doneness. Spread the mustard aioli on the toast and top with the braised kale. Place a fried egg on top and garnish with sliced radish, crumbled feta, red chili flakes, sesame seeds, and freshly cracked black pepper. Serve immediately.