Ingredient info: Tuscan kale, also called black kale, dinosaur kale, Lacinato kale, or cavolo nero, has long, narrow, dark green bumpy leaves; find it at farmers' markets and some supermarkets. Dried chiles de árbol are available at Latin markets, specialty foods stores, and some supermarkets.
For the slow cooked kale :
Bring a large pot of heavily salted water to a rapid boil over high heat. Working in 2 batches, blanch kale for 2 minutes. Drain, let cool, and squeeze out excess water with your hands. Coarsely chop; set aside.
Heat a large pot over medium heat for 2 minutes. Add 1/4 cup oil, rosemary sprig, and chile. Let sizzle, shaking pan often, for about 1 minute. Reduce heat to medium-low; add onion. Season with 1/2 teaspoon salt and a pinch of pepper. Cook for 2 minutes, stirring often; stir in garlic. Cook, stirring often, until onion is soft and starting to brown, 5-7 minutes. Add remaining 2 tablespoons oil and kale; stir to coat. Season with 1/4 teaspoon salt, reduce heat to medium-low, and cook, stirring often, until kale turns almost black and is slightly crisp at edges, about 30 minutes. Let cool. Discard rosemary and chile.
For the dressing :
Preheat oven to 400°F. Using your hands, toss bread in a large bowl while drizzling with 1/2 cup oil, squeezing bread to help it absorb oil. Spread out on 2 rimmed baking sheets, dividing equally; set aside.
Toast bread, stirring often and rotating baking sheets halfway through, until croutons are golden brown and crisp on the outside but still a little soft inside, about 20 minutes. Let cool; return to large bowl.
Meanwhile, toast fennel seeds in a small skillet over medium heat, shaking pan often, until seeds are fragrant and light gold, 2-3 minutes. Let cool. Using a spice mill or a mortar and pestle, coarsely grind fennel seeds; set aside. Alternatively, crush seeds in a resealable freezer bag with bottom of a heavy skillet.
Heat a large skillet over medium heat for 2 minutes. Add remaining 1/4 cup oil and butter. When butter is melted, add rosemary sprigs and chile; let sizzle in pan for 1 minute, then add crushed fennel seeds, fennel, onions, thyme, and garlic. Season with salt and pepper and sauté until vegetables are tender and lightly caramelized, 6-8 minutes. Discard rosemary sprigs and chile. Add vegetable mixture and Slow-Cooked Tuscan Kale to croutons.
Boil wine in same skillet over mediumhigh heat until reduced by 3/4, 1-2 minutes. Add broth; bring to a boil. Add to crouton mixture; toss well. Season with salt and pepper. Add eggs; stir to distribute. Transfer to a 13x9x2" baking dish. Cover with foil.
Bake dressing until heated through, about 30 minutes (a knife inserted into the center should be hot to the touch). Remove foil and bake until bread is golden and crisped on top, 25-30 minutes longer.
