1 sheet frozen puff pastry, thawed
5 large eggs
1 1/2 cups granulated sugar, plus more for sprinkling
1/2 cup, plus 2 tablespoons unsweetened cocoa powder
1 tablespoon instant coffee granules
1/2 teaspoon kosher salt
12 tablespoons (1 1/2 sticks) salted butter, melted
1 tablespoon bourbon ((optional))
1 tablespoon vanilla extract
1/2 cup semi-sweet chocolate chips or chunks
ice cream, for serving