For the crust place all crust ingredients in a food processor and process until it looks like like cornmeal. Press into a tart pan and bake for about 15 minutes until golden brown at 375°F See notes below for tips.
Place the hulled and halved strawberries in a bowl. Sprinkle them with sugar and pour over the Grand Marnier. Toss them around a bit so they are fully coated. Allow them to marinate for about 30-45 minutes. Strain and reserve the juice.
To make the custard place milk and vanilla bean in a saucepan and bring to a boil over medium heat. Remove from heat and allow to cool slightly. Scrape the pulp from the bean and add to the milk. Discard the bean pod.
In a bowl whisk egg yolks and sugar until combined. Add flour and mix well.
Slowly whisk in the milk mixture a little at a time to temper into the egg-sugar mixture. Once half of the milk had been added to the egg-sugar mixture whisk the eggs into the saucepan.
Return the sauce pan and cook for about 10 minutes on medium heat until mixture begins to thicken. Whisk continuously while it thickens.
To assemble the tart evenly spread custard on bottom of crust. Chill the filled shell in the refrigerator for 20 minutes until set. Place individual strawberry halves on top of custard. Serve individual pieces with a drizzle of the reserved syrup.