Position a rack in the lower third of the oven. Preheat the oven to 375° F.Butter an 8-10 inch skillet. Fit the puff pastry into the skillet, allow the sides to overhang. Lightly prick the bottom of the dough with a fork. Line the pastry with parchment paper and fill with pie weights, beans, or rice. Bake until the pastry is set, 15 minutes. Remove pie weights, sprinkle the pastry with 1 tablespoon sugar and continue baking until the pastry is golden, 5 minutes. Remove from oven. Reduce the oven temp 350°F.Meanwhile, whisk together the eggs and 1 1/2 cups sugar until well combined. Add the cocoa powder, instant coffee, and salt. Whisk in the melted butter, bourbon, and vanilla, until smooth. Fold in the chocolate chunks. Pour the mixture into the baked pastry.Bake for 40-50 minutes, until the cake is puffed on top, but still wiggly in the center. The longer you bake, the more set your cake will be. Remove from the oven and let cool 10 minutes. Serve the cake warm with ice cream.