Make the dough
Pulse the flour, hazelnut meal, sugar, and salt in a food processor to blend. Add the butter pieces and pulse until clumps the size of small peas form. Add the water, and pulse until the dough forms a loose ball. Split the dough onto two large pieces of plastic wrap and shape them into two flat disks about 6 inches in diameter. Wrap the disks and refrigerate until well chilled, at least 1 hour or up to 2 days.
Make the caramel
In a 2-quart heavy-duty saucepan, combine the sugar, butter, and salt with 2 Tbs. water. Cook over medium-high heat, stirring, until the butter melts and the sugar dissolves. Reduce the heat to low and cook, swirling the pan occasionally, until the mixture turns deep golden brown, 5 to 8 minutes. Remove from the heat and pour in the cream. Be careful; it will spatter. Return the pan to the heat and cook, stirring, until smooth, about 1 minute. Set aside to cool until warm.
Roll out the dough
Coat a 9- to 9-1/2-inch fluted tart pan with a removable bottom with cooking spray.
Let the dough sit at room temperature for 5 to 10 minutes to soften slightly, if necessary. Lightly dust a work surface and rolling pin with flour and roll one disk into a 12-inch round, lifting and turning the dough several times as you roll to prevent sticking, and dusting the work surface and the rolling pin with more flour as needed. Carefully roll the dough up around the pin, and unroll it over the prepared tart pan. Gently fit it into the pan without stretching. Run the rolling pin over the top of the pan to trim the dough even with the edge. Cover and refrigerate until the tart shell is firm, at least 30 minutes.
Meanwhile, roll the other disk into a 10-inch round. Using a fluted pastry wheel, pizza cutter, or a sharp knife, cut the dough into seven 1-inch-wide strips. Transfer the strips to a lightly floured large flat plate or small baking sheet, cover with plastic wrap, and refrigerate until ready to use.
Assemble the tart
Position a rack in the lower third of the oven, place a cookie sheet on it, and heat the oven to 400°F.
In a medium bowl, toss the apples and pears with the flour, cardamom, and salt. Arrange in an even layer in the crust. Drizzle the caramel evenly over the fruit (if hardened, melt briefly over low heat). Evenly space 3 strips of pastry on top of the tart. Evenly space the remaining 4 strips over the other strips at a 45° angle. Press the edges of the strips into the edge of the tart shell to secure. Dot the tart with the butter in between the strips.
In a small bowl, whisk together the egg yolk, cream, and 1 Tbs. water. With a pastry brush, coat the lattice strips with the egg mixture. Sprinkle with the sanding sugar.
Bake the tart on the heated cookie sheet until the filling is bubbling and the crust is golden brown, 40 to 45 minutes. Transfer the tart from the cookie sheet to a rack to cool completely, at least 2 hours and up to 1 day. Remove the outer rim from the tart pan and transfer the tart to a large, flat plate before serving.
nutrition information (per serving):
19, Fat Calories
170, Saturated Fat
4, Monounsaturated Fat
42, Polyunsaturated Fat
Photo: Colin Clark