For the Oreo cookie base:

1. Preheat oven to 350 degrees F
2. Prepare an 8 inch by 8 inch baking pan by lining the pan with aluminum foil leaving an overhang coming up the sides to easily lift the bars out of the pan. Alternatively use a non-stick, removable bottom pan. Spray the inside with cooking spray.
3. Combine the Oreo cookie crumbs and the melted butter. Press into the bottom of baking pan.
4. Bake in 350 degree F oven for 5-8 minutes until set.
5. Remove from oven and let cool. Let chill in freezer while preparing the filling.

For the filling:

1. In the bowl of a stand mixer with the paddle attachment, beat the softened butter and the sugar on medium-high for 5 minutes until pale in color and light and fluffy, stopping to scrape down the sides of the bowl half-way through.
2. Add the salt, vanilla, coffee granules, and cooled, melted chocolate and beat for another 5 minutes. Scrape down the sides of the bowl.
3. Using the whisk attachment, one by one, add the eggs and beat for a full 5 minutes after the addition of each egg, for a total of 20 minutes. Beating the full 20 minutes is essential. Scrape down the sides of the bowl before the addition of each egg.
4. Pour the filling into the prebaked crust and refrigerate for several hours or overnight.
5. Before serving, top with lightly sweetened whipped cream and chocolate shavings or curls.
6. Store the French Silk Pie Bars in the refrigerator.