In a medium saucepan over medium heat, add the pears, water, sugar, vanilla extract, cinnamon, and nutmeg. Let the mixture come to a boil, then reduce the heat to poaching temperature (160F - 180F). If you don't own a kitchen thermometer, poaching happens when there are gentle waves on the surface of the water and small bubbles at the bottom of the saucepan (bubbles shouldn't rise to the surface).
Poach for 25-30 minutes or until pears are fork-tender. You can use a piece of parchment paper cut to fit the inside dimension of your saucepan to keep the pears submerged into the poaching liquid.
Allow the pears to cool slightly in their liquid and serve. If you want to use the pears for a cake, remove them from the liquid, place them onto a clean plate and allow them to cool down completely before adding them to your cake batter.
Notes
Storing Instructions: you can store them covered in their liquid in the refrigerator for 10 days. If you want to use your poached pears to make a poached pear cake, I wouldn't store them for longer than 3-4 days.Poached pears stored in their poaching liquid will keep absorbing the liquid & spices so the flavor will intensify over time.