- Preheat the oven to 350°F. Grease a 9x13-inch baking dish with the butter.
- In a large skillet, cook the bacon over medium-low heat until crispy, 8 to 10 minutes. Transfer the bacon to a plate lined with paper towels and set aside. When cool enough to handle, chop into roughly 1/4-inch pieces.
- Pour off all but 2 tablespoons of the bacon grease from the pan. Set the skillet over medium-high heat, add the onion, and sauté until soft and lightly browned, about 4 minutes. Add the kale and garlic and sauté until the garlic is tender and fragrant, another 3 minutes. Remove from the heat.
- Add the chopped bacon to the onion/kale mixture.
- In a large bowl, whisk together the eggs, milk, and mustard. Add 1/2 cup of the mozzarella, 1/2 cup of the Gruyère, the hash browns, salt, and pepper. Mix well.
- Stir the kale mixture into the eggs, then pour into the buttered dish. Top evenly with the remaining mozzarella and Gruyère. Cover with foil.
- Transfer to the oven and bake for 45 minutes. Remove the foil and bake, uncovered, for 15 minutes, until the top is lightly browned and bubbly.
- Serve hot.
- Store in an airtight container in the refrigerator for 3 to 5 days.
“Magnolia Table: A Collection of Recipes for Gathering, Volume 2” by Joanna Gaines © William Morrow 2020. Provided courtesy of Joanna Gaines. All rights reserved.