In a large mixing bowl, combine flour, sugar, and salt. Cube cold butter into dry ingredients and mix until resembling coarse crumbs. Gradually add ice water until dough holds together. Shape into a disc, wrap in plastic, and refrigerate for at least 30 minutes.

Preheat your oven to 375°F (190°C). In a mixing bowl, toss sliced pears with brown sugar, flour, chai spice, ginger, and cardamom until evenly coated. Allow to sit for 10 minutes.

In another bowl, combine rolled oats, chopped almonds, brown sugar, and melted butter until crumbly. Set it aside.

Roll out chilled pastry on a floured surface to 1/8 inch thick. Fit into a tart pan, pour in pear filling, and sprinkle crumble topping over the fruit.

Bake for 40 to 50 minutes or until crust is golden and filling is bubbling. Cover with foil if topping browns too quickly.

Cool the tart for at least 15 minutes before serving. Enjoy warm or at room temperature with ice cream or whipped cream.