Preheat oven to 425°F and prepare a 9-inch pie dish.
Roll out half of the pie dough and fit it into the dish.
In a saucepan over medium heat, combine water, sugar, and cream of tartar, stirring until sugar dissolves.
Bring to a gentle boil, then reduce heat and simmer for 5 minutes.
Stir in lemon juice, cinnamon, and nutmeg.
Lightly crush crackers and add them to the mixture. Remove from heat.
Pour the filling into the pie crust, dot with butter, and cover with the second crust.
Crimp the edges, cut slits for steam, and bake for 30 minutes, until golden brown.
Let the pie cool completely before slicing—this helps the filling set.