Pre-heat the oven to 200 degrees. Add flour, salt and sugar to a food processor or blender. Slowly and add cold pieces of butter and blend until it resembles coarse meal. At this point, start slowly adding the ice water, about a tbsp at a time. If you don't have a blender, you can also do this with two table knives and your hands. Press the dough into a flat ball, wrap it in plastic wrap and make sure to refrigerate for AT LEAST 1 hour, up to overnight.
About 30 minutes before you are ready to work the dough, make the filling. Place the chocolate chips and butter into a glass oven safe bowl, and place in the preheated oven, stirring occasionally until fully melted. Set aside once melted.
In a saucepan, bring the maple syrup and sugar to a boil, and simmer for 2 minutes. Whisk the eggs in a bowl, then add the melted chocolate butter mixture and the syrup. Blend throughly, add the almonds, cocoa powder and vanilla extract, and set it aside to cool.
Transfer the cooled dough from the refridgerator to a lightly floured surface. Cut the dough circle in half. Roll one half out until it is about 13" by 13", and fits into your tart shell Cover the tart shell with plastic wrap and place it in the fridge until ready to use.
Pre-heat the oven to 400 degrees. Roll out the second half of dough on a floured baking surface until it is less than 1/8" thick. Using a pastry wheel or pizza cutter, cut the dough into 1/2 inch wide strips.
Whisk an egg in a bowl and egg wash one of the strips. Sprinkle with red sanding sugar and place on a piece of parchment paper. The next two strips above and below this strips should be plain strips of dough. Every red strip should be egg washed so the sprinkles stick. Lay the dough, red-plain-red-plain and so on, with a 1/2 inch space between each, until you have a surface of about 13 inches. Do the same thing in the opposite direction, except weave the dough under/over the previously layed dough. When finished, adjust the strips to try to make sure there are no spaces in the pattern. Transfer the parchment and lattice to a flat baking sheet and place it in the freezer for about 8 minutes. Take the pie crust out of the fridge and fill with the chocolate almond mixture. When the lattice is done cooling, position the parchment paper directly next to the tart. Carefully slide your hand under the lattice, so your hand is positioned in the middle of it. Lift up and carefully transfer the lattice to the top of the pie (this should be easy with the dough cooled). Trim the edges.
Bake for 20 minutes at 400 degrees, then lower the heat to 350 and bake for about 25 minutes. The edges should be begining to turn golden. Allow the tart to cool to room temp before cutting, and enjoy!