Place all the ingredients in a wide-rimmed saucepan or Dutch oven over medium-low heat. Simmer, stirring occasionally, until the pears have softened and the mixture has thickened about 50 minutes. 

Using an immersion blender, puree the mixture until creamy and smooth. Alternatively, let the mixture cool slightly, then transfer to a food processor and puree until creamy and smooth. 

Enjoy as is, or return to the saucepan to simmer for longer to create a thicker, darker pear butter. 

Transfer to a jar and store in the fridge for up to 2 weeks. 

Alternatively, you can water bath can this pear butter by ladling the pear butter into clean, hot jars. Wipe clean the rims of the jars, then fasten them with a lid and seal. Place in a boiling water bath for 10 minutes, then remove using canning tongs and allow to cool at room temperature. Check the lids by pressing on the center of each seal. If it springs back, the jars should be refrigerated. Otherwise, store it in a dark, cool place, like a pantry, for up to a year.