Make the crust

1. Position a rack near the center of the oven and heat the oven to 400°F or 375°F convection. In a small bowl, mix the egg yolk, milk, and vanilla. Put the walnuts in a food processor and pulse until finely chopped. Remove to a medium sized bowl. Add the flour, sugar, and salt and stir until thoroughly combined. Add the melted butter and the yolk mixture. Stir well, then using your hands, mix until thoroughly combined. The dough will be a mealy, crumbly mass.
2. Pour the crumb mixture into a 9-1/2-inch round fluted tart pan with a removable bottom. Starting with the sides of the pan, firmly press the crumbs against the pan to create a crust about 1/4 inch thick. Press the remaining crumbs evenly against the bottom of the pan. Freeze for 10 minutes. Place on a rack inside a baking sheet and bake until the sides just begin to darken and the bottom is set, about 20 minutes. Reduce the oven temperature to 350°F or 325°Convection.

Make the filling

1. Peel the pears, quarter them lengthwise, core, and cut crosswise into 1/4″ slices.
2. In a food processor, coarsely chop the cranberries. In a medium bowl, mix the pears, cranberries, and brandy. In a small bowl, mix the sugar, flour, ginger, cinnamon, allspice, and salt; add to the cranberry-pear mixture, tossing to combine. Spoon the filling into the partly baked crust, levelling the filling and packing it down slightly with the back of a spoon.

Make the streusel and bake

1. In a small bowl, mix the flour, brown sugar, and salt. Add the melted butter and vanilla. Combine with your fingers until the mixture begins to clump together in small pieces when pressed. Sprinkle the streusel over the filling, breaking it into smaller pieces if necessary.
2. Bake at 350°F or 325°F convection until the fruit is tender when pierced with a fork and the streusel and the edges of the crust are golden brown (about an hour). If the tart begins to get overly brown at the edges, cover with foil. Let the tart cool on a rack until it’s just barely warm before serving.