Preheat oven to 375 degrees. In a large skillet over medium-high heat, combine olive oil and 4 tablespoons butter. Once the oil and butter has melted, add the garlic and leeks. Season with salt and pepper and cook, stirring occasionally, until leeks are bright green and softened about 8 to 10 minutes.
Then add celery, and season with salt and pepper. Cook, stirring occasionally until bright green and tender, 4 to 6 minutes. Add white wine, and cook until reduced by about three-quarters, 3 to 4 minutes. Remove from heat.
Whisk together broth and eggs in a medium bowl. Place bread in a large bowl big enough for mixing. Add the leek and celery mixture, parsley, chives and marjoram. Stir to coat so that everything is evenly distributed. Pour the egg mixture over everything and toss a few times. Let sit a minute or two and give another toss. Repeat twice until all the liquid has absorbed and evenly distributed to each and every piece of bread.
Transfer mixture to a 2 1/2- to 3-quart baking dish (a 9-by-13 pan also works), making sure not to pack it too tightly. Dot the top with the remaining 4 tablespoons butter, making sure to pay extra attention to the corners, where the stuffing will get the crispiest.
Cover with foil and bake until the stuffing is sizzling at the edges and completely cooked through, 25 to 30 minutes. If it’s not yet time to serve, remove stuffing from oven and set aside.
When ready to serve, remove foil and increase temperature to 425 degrees. Bake stuffing until crispy, crunchy and deliciously golden brown on top, 20 to 25 minutes. Sprinkle some chopped parsley on top if desired.