In the mixing bowl, add the eggs, heavy cream, melted butter, vanilla, cinnamon, allspice, and salt to the squash, mixing thoroughly with a whisk or hand mixer to break up all the chunks of squash into a smooth, even texture. Pour into an 8x8 baking dish greased with coconut oil or butter. Cook in the oven for 30 minutes, or until the casserole is turning slightly golden brown on top. Meanwhile, toast the pecan pieces in a sauté pan on medium high heat for 4-6 minutes, tossing often and being careful not to burn. Top the acorn squash casserole with the toasted pecan pieces then serve.