Prepare Tart Shell

In food processor with steel blade, add flour, sugar, salt, pulse to blend 5 seconds. Add chilled cubed butter, process 5-10 seconds until coarse meal is formed.  Mix egg yolk and 1 tablespoon ice water in custard cup, add to processor, process until dough forms a ball around the sides of bowl. If needed add additional 1 tablespoon cold water. Remove from bowl, pat into a disc, wrap and chill for at least 30 minutes or over night.

Rolling Dough 

On floured surface, roll disc to 1/4″ thickness 10″ round. Lightly spray 9″ spring form pan with cooking spray.  Wrap dough around rolling pin then place in tart pan extending crust one inch beyond tart edges. Smooth tart dough into bottom and up sides of tart pan. With excess dough around the edged, fold back inside tart shell edge creating a thicker edge. Smooth sides and bottom of tart shell with piece of parchment paper. With sharp knife cut horizontally across the top edge of the tart pan, use leftover dough to patch any weak spots in crust. Dock or prick dough with a fork. Chill tart shell for  30 minutes. Preheat oven to 475 F. Place chilled tart crust on baking sheet and place in oven middle of oven. Bake tart shell for 17-20 minutes or until golden brown. Remove from oven and set aside to cool. 

Caramel Sauce

In medium saucepan over medium heat, add sugar, do not stir sugar in pan. Swirl the sugar around the pan until it fully melts, add butter, continue to swirl and then stir with wooden spoon or wire whisk, add room temperature heavy cream, whisk until smooth and creamy. Place caramel in a medium mixing bowl to cool down, then pour into a baked tart shell. Chill tart in refrigerator while you make the ganache.

Making the Ganache Filling

In microwave safe measuring cup, heat heavy cream for 25 seconds up to 55 seconds or until very warm but not boiling.  In a medium mixing bowl, add 2 cups chocolate chips or 11 ounce package to bowl.  Pour warm cream over the chips.  Allow to chips and cream to sit for 5 minutes before stirring. Stir until thick, creamy smooth and shiny. 

Pour ganache into cooled caramel filled  tart shell, smooth evenly with off set spatula. Sprinkle with coarse sea salt.  Place in refrigerator to set at least 4 hours before serving.

Serve tart with fresh whipped cream if you would like. Recipe makes 6-8 servings depending on your slice widths. This is a very rich tart, smaller servings are recommended.