In a medium bowl, combine the flour, salt, sugar, and softened butter by hand with a large spoon (not a mixer). Add the water 1 tablespoon at a time until the mixture comes together and forms a dough. It should not be crumbly.

Press the dough into a round disk, cover in plastic wrap, then refrigerate for 30 minutes or overnight.

Roll out the dough on a lightly floured work surface, adding more flour as needed to prevent the dough from sticking to the counter or the rolling pin from sticking to the dough.

To roll out the dough place the rolling pin in the center of the dough and press and roll outwards. Lift the dough, turn it 90 degrees, and repeat. This prevents the dough from sticking to the counter.

Continue to roll out the dough (avoiding pressing too hard at the edges to avoid tapered edges) until the dough is large enough to fit in the pie dish with ½-1 inch of overhang.

Tuck any crust that hangs over the dish over the outer edge (rather than tucking in towards the center) and press it to create a nicely rounded and thicker top crust.

Flute the edge of the pie crust with the knuckle of your index finger on your nondominant hand and your thumb and index finger on your dominant hand. Place the pie dish flat in the freezer while you work on the filling.

Preheat the oven to 350℉.

Place the walnuts on a baking sheet and toast them at 350℉ for 8 minutes.

In a large microwave-safe mixing bowl add the dark chocolate chips. Microwave for 1 minute at 50% power, stir, and add 30 seconds as needed until it has melted. Add the melted butter and stir to combine.

Add the maple syrup and combine. Ensure that the batter is at room temperature. It should not be hot, or it will cook the eggs. Then add the 2 eggs and 1 egg yolk and mix thoroughly to combine.

Sift in the flour.

Add the toasted walnuts and stir to combine.

Remove the pie crust from the freezer. Pour the filling into the pie crust.

Combine the egg white and 1 teaspoon water. Brush on the fluted edges of the pie crust.

Bake the pie at 350℉ for 45-50 minutes or until the crust starts to turn brown. Check the crust at the 30-minute mark and cover if needed to prevent the crust from burning.

Allow the pie to cool, but serve warm topped with vanilla ice cream.