In a large bowl, combine flour and sugar. Make a well in the center then tip in the butter cubes and egg yolk. With your fingertips, crumble everything together, achieving an appearance of coarse meal. It will be crumbly, but will hold together when you squeeze a handful. If it does not hold, add ½ tsp of water and work in.
Preheat oven to 375 F.
Sprinkle and press into a 9” (10” Maximum) tart pan, starting with sides. Make a flat top with right angles where the bottom meets side then flatten bottom using a drinking glass as a tool. Let chill for 30 minutes. Bake about 20 minutes until it starts browning and set aside.
On a parchment lined baking tray, spread the pecans out and bake 5 minutes or just until you can smell toasting. Bake no more than 7 minutes total. Set to the side.
Over medium heat, melt butter in a medium saucepan, then add brown sugar, maple syrup, salt and vanilla extract. Finally gently stir in cornstarch into cold cream until smooth then add to saucepan. Stir constantly with a spatula while bringing just to the boil for 30 seconds. Turn off heat, stir in pecans, then scrape out into tart shell.
Bake at 375 Convection until set, about 20 minutes.