Step 1

For the crust: Knead the 2 flours with the butter and sugar until the mixture resembles coarse meal, then mix in the egg yolk. Shape the dough into a ball, cover it, and refrigerate for 2 hours.

Step 2

Preheat the oven to 340°F.

Step 3

Roll dough out into a thin sheet (1/8" thick) and line bottom and edges of a round springform pan (7" diameter, 1" deep) with it, cutting off any excess dough. Pierce bottom of the dough with a fork, line with parchment paper, and cover with pie weights (you can also use dried beans). Bake the crust at 340°F for 20 minutes; remove parchment paper and weights and cook for another 5 minutes. Remove from oven and increase oven temperature to 350°F.

Step 4

For the frangipane: In a food processor, process pecans and brown sugar to a fine paste, around 2 minutes. Add softened butter, maple syrup, 1 egg, and a pinch of salt; pulse until smooth. Pour mixture into the crust and bake at 350°F for 12-15 minutes.

Step 5

For the topping: Juice both lemons and set aside. Peel and core the green apple and cut into small pieces. Cook in a saucepan with 1/2 of the lemon juice for 10 minutes, then add 1 Tbsp. maple syrup and continue cooking for another 2 minutes. Let cool and arrange over the tart. Brush the edge of the tart with a little maple syrup and scatter a handful of chopped pecans over it.

Step 6

Prepare a simple syrup by dissolving the sugar with 1 cup water and remaining lemon juice over medium heat. Bring to a boil and remove from heat. Cut remaining apples into thin slices, removing the core and seeds. Leave peel on. Dip slices in the syrup. Let excess syrup drip off, and arrange in a spiral on top of the tart.