Preheat the oven to 400 degrees. Roll out the dough into a 13-inch circle. Place the dough into an 11-inch round fluted tart pan. Press the dough into the edges. Roll the rolling pin across the top to form a clean edge. Lay a piece of parchment paper over the dough cover with pie weights or dried beans, and bake for 15 minutes. Remove the parchment and weights and bake another 10 minutes. Remove from the oven and let cool. While the crust is cooling, make the filling. Toss the squash with 1/2 T. of the olive oil, 1/2 tsp. salt, and the nutmeg on a rimmed baking sheet. Spread evenly on the sheet, and bake for 25 minutes. Remove from the oven and set aside. Heat a large sauté pan over medium-high heat. Add 1 1/2 T. olive oil and heat through. Add the garlic and sauté for 2 minutes. Add the kale and cook for 5-7 minutes until it begins to soften. While kale cooks, add the red pepper flakes and pinch of salt. Transfer to a large mixing bowl and set aside. In the same sauté pan, heat the remaining 1/2 T. olive oil over medium heat. Add the onion and a pinch of salt; cook for 20 minutes, stirring every couple minutes. Add the balsamic vinegar, stir, and remove from the heat. Set aside to cool. Squeeze out any excess liquid from the kale and return to the bowl. In a separate bowl whisk the eggs until blended well and add to the kale. Add three-fourths of the squash, half the cheese, the onion, and a few grinds of black pepper to the kale-egg mixture. Stir together and add to the cooked crust. Scatter the remaining squash and cheese over the top, and add a few more grinds of black pepper. Bake until the egg is set and the top is lightly browned, 25-28 minutes. Remove from the oven and allow it to cool for 5 to 10 minutes before serving.