Warm the Skillet and Add Oil: Place a 10-12 inch cast iron skillet over medium-high heat. Once hot, pour in the avocado oil and swirl it to coat the bottom evenly. Let the oil heat until it releases a subtle aroma but doesn’t smoke.
Sauté the Butternut Squash: Add the cubed butternut squash to the skillet. Stir frequently to ensure the cubes cook evenly and develop a tender, slightly caramelized exterior. This should take about 5 minutes.
Cook the Onion Until Soft: Add the chopped onion to the skillet with the squash. Continue to sauté both ingredients together, stirring occasionally, until the onion becomes translucent and tender, about 5 more minutes.
Incorporate Sausage and Aromatics: Stir in the sliced turkey sausage, minced garlic, and fresh thyme. Cook for an additional 1-2 minutes, allowing the garlic and herbs to infuse their flavors into the hash while the sausage warms through.
Wilt the Spinach: Add the chopped spinach to the skillet. Cook, stirring gently, until the spinach has wilted completely, roughly 3-5 minutes.
Add Eggs and Finish Cooking: Using a spoon, create four small indentations (“nests”) evenly spaced in the hash. Crack one egg into each nest carefully. For baked eggs, transfer the skillet to a preheated oven at 350ºF and cook for 15-20 minutes until eggs are set to your liking. Alternatively, cover the skillet on the stovetop, reduce heat to low-medium, and cook for 7-10 minutes until eggs reach desired doneness.
Season and Serve: Remove the skillet from heat. Sprinkle with salt and freshly ground black pepper to taste. Serve warm and enjoy your hearty breakfast!