Cook The Pears: In a large, heavy-bottomed pot, heat the butter on medium until melted. Add the pears, cider, and lemon juice. Cook, stirring occasionally, 10 to 12 minutes, or until the pears begin to break down. Cover and reduce the heat to medium-low. Cook, stirring occasionally, 60-65 minutes, or until softened and broken down.
Make The Pear Purée: Transfer the cooked pears to a blender. Blend on high until smooth. (For a more rustic texture, skip this step and add the spices next.)
Cook The Pear Purée: Return the pear purée to the same pot. Add the sugar, cinnamon, nutmeg, allspice, and salt. Heat on medium until hot. Cook, stirring occasionally and scraping the bottom of the pot to prevent scorching, 6 to 8 minutes, or until thickened.
My favorite way to enjoy this pear butter is on toast. Delicious!