I set my oven rack to the middle position and preheat it to 450°F. While it heats up, I chop the sweet potatoes, yellow potatoes, and onion into similar-sized ½-inch pieces so they cook evenly. Keeping the pieces uniform really does make a difference in how the potatoes turn out.
I toss the sweet potatoes, yellow potatoes, and onion in a large bowl with olive oil, salt, and pepper until everything is evenly coated. Then I spread it all out in a single layer on the sheet pan. Roasting for 15 minutes gets the potatoes most of the way tender before the next step.
After the initial roast, I leave the pan in the oven and switch it to high broil for 3 to 5 minutes. This step gives the potatoes that golden, slightly crisp edge that makes the whole dish so much better. I keep a close eye on it since broilers work fast.
Once the potatoes are done broiling, I pull the pan out and switch the oven back to 450°F. Using the thin edge of a metal spatula, I gently release any potatoes stuck to the pan and toss them again. This keeps every piece coated and ready for the next layer.
Next, I shape the potatoes into six even sections and press a small well into the center of each one. I place two turkey sausage links on either side of each well so they warm through with everything else. This is where the sausage and sweet potato recipes really start coming together into one dish.
I sprinkle the cheddar, Parmesan, and parsley over the potatoes and sausage, then lightly spray each well with cooking spray. Gently, I crack one egg into each well so it sits right in the center. This step needs a light hand so the yolks stay intact.
I slide the pan back into the oven for 3 to 4 minutes for eggs with a soft, jammy center. Since the pan stays hot after it comes out, the eggs keep cooking a little longer, so I always pull them slightly underdone. If I want firmer yolks, I add an extra minute or two.
I let the pan rest for a few minutes before slicing it into six portions. Using a metal spatula, I lift each egg-and-sausage square out carefully so the yolk stays whole. From here, it's ready to eat immediately or pack away for the week.