Preheat oven to 400F with rack on lower middle position. Lightly grease a 9×13 baking dish and set aside.

On a large baking sheet, combine sweet potatoes with 2 TB olive oil, ½ teaspoon kosher salt, and ¼ teaspoon freshly ground black pepper; toss to coat well. Bake in a single, even layer for 20 minutes until soft. Remove sweet potatoes from oven.

Meanwhile, heat remaining 2 TB olive oil on a large skillet over medium high heat. Add onions and garlic and stir 2-3 minutes or until translucent. Add peppers and stir 1 more minute. Transfer mixture to prepared 9×13 baking dish.

In the same skillet over medium high heat, cook and break apart sausage with spatula until cooked through. Drain and add to baking dish with veggie mixture. Add roasted sweet potatoes, and chopped kale to the mixture in baking dish. Gently toss to combine all ingredients well.

In a bowl, gently whisk together the eggs, ½ cup milk, 1 teaspoon kosher salt, and ¼ teaspoon freshly ground black pepper until well combined. Pour evenly over the sausage/potato mixture in baking dish. Bake uncovered about 25-30 minutes or just until eggs are set in center.