Serves 4 to 6 INGREDIENTS For soup 3 pounds winter squash (such as kabocha, acorn, or butternut), peeled and cut into 2-inch chunks 2 tablespoons extra-virgin olive oil 2 tablespoons unsalted butter 1 large or 2 medium Spanish onions, chopped (2 cups) Sea salt or kosher salt 1 tablespoon minced fresh ginger 3 garlic cloves,…