Step 1

Preheat oven to 375°F (190°C). Line a baking sheet with foil or parchment paper.

Step 2

Grease a 9 by 13-inch baking dish with 1 tablespoon of the butter.

Step 3

Scatter the bread pieces in one layer onto the prepared baking sheet. Drizzle the bread with half of the olive oil, toss, then bake, tossing a few times during cooking, until lightly browned and a bit crispy, 12 to 15 minutes. Cool and transfer to a large bowl.

Step 4

In a large skillet over medium-high heat, heat the remaining olive oil. Add the sausage and cook, stirring occasionally and breaking it into small pieces with a spoon, until browned and cooked through, 8 to 10 minutes. Use a slotted spoon to transfer the sausage to the bowl of bread. Reduce heat under the skillet to medium.

Step 5

Add to the skillet the celery, leek, and fennel, season with the salt and pepper, and cook, stirring often, until the vegetables start to soften, 6 to 8 minutes. Add the garlic powder, thyme, oregano, and sage and cook until leeks are golden and soft and the herbs are fragrant, 5 to 6 minutes more. Add the sauteed vegetables to the bowl with the bread mixture.

Step 6

In a medium bowl, whisk together the eggs and broth, then pour it over the bread mixture. Add the macadamia nuts, season generously with salt and pepper, and toss until combined and bread is hydrated. Transfer the mixture to the prepared baking dish, melt the remaining butter, and drizzle it over the stuffing.

Step 7

Cover with foil, then bake the stuffing for 30 minutes. Increase oven temperature to 425°F (215°C). Uncover and continue to bake the stuffing until its top is golden brown and crisp, 10 to 15 minutes. Let rest for 5 minutes. Serve.