Instructions
Step 1
Season the bacon to taste with salt and black pepper. In a large nonstick skillet over medium-high heat, melt the butter. When the foam subsides, add half the bacon to the skillet and cook, turning once, until caramelized on both sides and tender, about 8 minutes. Transfer to a plate, then repeat with the remaining bacon.
Step 2
Position a rack in the center of the oven and preheat to 400°F. Drain off all but ¼ cup of the rendered fat and return the skillet to medium heat. Add the onions and cook, stirring occasionally, until caramelized and soft, about 20 minutes. Stir in the thyme, remove the skillet from the heat, and scrape the onions into a 9- by 13-inch baking dish or small roasting pan.
Step 3
Add the apples to the onions, toss to coat evenly in the fat, and bake, stirring once halfway through, until the apples are just tender and lightly caramelized, about 20 minutes. Using tongs, push the apples and onions to one side of the baking dish and nestle the bacon slices next to them. Continue baking until the apples are very tender and the bacon is warmed through, about 10 minutes more. Transfer the dish to a wire rack and allow to cool for 10 minutes before serving.