Place the pears and water into a pot or large saucepan. Cook over medium heat until pears are soft, about 30 minutes. Sterilize six half-pint jars and keep warm.
Transfer pears to a food processor and pulse until they reach your desired consistency. Return to the pan, and stir in the brown sugar, lemon zest, nutmeg, almond extract and limoncello. Cook over medium-low heat, stirring occasionally, until the mixture reaches a thick consistency like butter, about 1 hour.
Ladle the pear butter into the sterile jars, leaving 1/4 inch headspace. Seal with lids and rings. Process in a hot water bath for 10 minutes to ensure a seal.