Preheat the oven to 350°F (180°C).
Butter a 9″ (23cm) square baking dish and line it with parchment paper.

Put the coffee in a bowl and pour the hot water over it. Set aside.
Mix the butter, peanut butter, sugar, and dissolved coffee until creamy.
Combine the cornstarch and flour, then add to the mixture to form a homogeneous dough.

Spread the dough at the bottom of the baking dish and poke it with a fork.
Bake for 20 minutes.

For the filling:
Heat the butter, brown sugar, and molasses until the butter has melted. Bring to a boil.
Let it cool for 5 minutes, then stir in the chopped pecans.
Spread the filling over the crust.
Let it cool in the baking dish, then remove from the dish and cut into bars.