Bring a large pot of water to a boil. Blanche the sweet potato cubes for 2 minutes. Drain and rinse them under cold water. Drain well. Place the potatoes in a medium bowl.
Add the maple syrup, rosemary and salt and pepper to taste and give it all a good toss. Put the bowl in the refrigerator for about 15 minutes.
Heat a large frying pan over medium heat and then add the butter and shallot. Just as the shallots begin to soften, add the sweet potato and any liquid that's collected at the bottom of the bowl as well as the sprigs of thyme.
Sauté over medium-high heat for 15 to 20 minutes, stirring occasionally. You want the sweet potatoes to get a crisp, toasty brown. Then add your kale to the pan and gently mix it into the potatoes. Allow it to cook for about 3 to 5 minutes.
Meanwhile, heat a separate, large frying pan over medium heat. Once the pan is good and hot, melt a pat of butter and then slowly crack all four eggs into it. Just let the eggs sit. Allow the eggs to cook until the whites are set and the edges start to curl up. If the whites in the middle of the eggs are not set, but your edges are browned and curled, you can cover the pan for 2 minutes.
Serve a hearty scoop of hash with a fried egg on top.