- Preheat oven to 325 degrees.
- For bar base/crust, in the bowl of a food processor pulse pecans and graham crackers until finely ground. Add sugar, salt, and cocoa, and mix until well-lended. Dump contents into a mixing bowl. Add melted butter and process until moistened.
- Reserve 2 tablespoons of the chocolate crumb mixture for topping. Press remainder of wet crumb mixture into an 8-inch square baking dish with fingers. Bake crust for 10 minutes, until set. Transfer to a wire rack to cool.
- For filling, melt butter with chocolate in a medium saucepan set over medium heat, stirring constantly. Remove from heat and stir in flour and salt until smooth. Stir in sugar, honey or sorghum, espresso, and vanilla. Add the eggs, one at a time, stirring until smooth.
- Pour filling into the prepared crust and bake until set and cracked on top, about 30 minutes. Transfer to a rack and cool slightly.
- For whipped cream, beat cream, sugar, and vanilla with hand mixer until soft peaks form. Top bars with whipped cream, a drizzle of honey or sorghum, and reserved crust mixture.