Preheat the oven to 350 degrees F. In a small bowl, stir together the ginger, cinnamon, cardamom, cloves and allspice until mixed. This is your chai spice!
Place the pears in a large bowl. Sprinkle them with sugar and salt. Sprinkle on half of the chai spice you just made. Stir together so everything is combined. Let them sit for 5 or 10 minutes. Sprinkle on the vanilla extract and stir.
In another bowl, stir together the flour, oats, sugar, salt and the remaining chai spice. Stir in the melted butter and mix until everything is moistened and the mixture is combined.
Place the pears in a baking dish - either a 9 inch pie plate, a 9x9 inch square dish or something similar. Sprinkle all over with the oat mixture.
Bake for 45 to 55 minutes, or until the crisp is golden and crunchy. If at anytime it gets too dark in color, you can tent with foil.
Remove and serve with vanilla ice cream!