Preheat the oven to 425 degrees F.
On a parchment-lined baking sheet, toss the fennel with 1 tablespoon of olive oil and 1/2 teaspoon salt; arrange in an even layer. On a second parchment lined baking sheet pan toss the squash with 1 tablespoon olive oil and 1/2 teaspoon sea salt; arrange in an even layer. Transfer the vegetables to the oven and roast for about 30 minutes, or until tender and caramelized, switching the pans halfway through. Set aside.
Meanwhile, in a large heavy-bottomed skillet heat 2 tablespoons of olive oil. Add the garlic and cook over low heat until golden brown and fragrant. Remove the cloves to a heat-proof bowl and cover with an additional 1/4 cup of olive oil.
Add the pork to the skillet and cook, stirring occasionally and breaking apart into small pieces with your spatula, until nicely browned, about 7 minutes. Stir in the rosemary and red pepper flakes, and season generously with salt. Cook one minute more, then add the wine. Scrape up any brown bits on the bottom of the pan and simmer for two minutes, or until the alcohol has burnt off. Set the sausage mixture aside to cool.
Turn the oven temperature down to 375 degrees F.
Remove the garlic cloves from the olive oil and discard. In a large bowl, toss the bread with the reserved garlic-infused olive oil. Season generously with salt and pepper. Remove the parchment from one of the sheet pans and add the bread in an even layer. Toast in the oven for 10 to 15 minutes, until lightly browned.
Meanwhile, in the same bowl, whisk together the egg and chicken stock. Add the squash, fennel, sausage and green scallions. Fold in the toasted bread until well coated, then turn the whole mixture out onto the sheet pan. Cover with foil and return to the oven for 20 minutes. Remove the foil and cook another 15 minutes, or until golden and crusty. Remove the pan from the oven and let the stuffing stand for 10 minutes before serving.