Preheat the oven to 350 degrees. Butter a 11x7 glass pan.
To make the crust, grind crackers and sugar in a food processor until crumbs. Add melted butter and espresso powder. Process to blend and press 1/2 of the mixture into your prepared pan. Put the other 1/2 of the mixture into a pie dish. Bake both until golden, ~10 minutes. Cool 10 minutes.
To make the filling for the bars, beat cream cheese and 2/3 cup sugar. Beat in egg, then cream, vanilla, and espresso powder.
Spread mixture over the crust. Bake until set, ~25 minutes. Chill uncovered 2 hours or overnight.
To serve, beat heavy cream with the sugar and vanilla until thick and creamy (or use store bought whipped cream). Sprinkle reserved crumb mix from your pie plate over the bars, and cut bars into squares. Serve with a dollop of whipped cream. Enjoy!