Preheat oven to 350 degrees (325 degrees if you have a dark-colored pan). Line 9x9 square baking pan with parchment paper or aluminum foil. Spray with non-stick spray. Set aside.
In a small bowl, whisk together the dry ingredients from the brownies: flour, sugar, cocoa, espresso powder, baking powder, and salt. Set aside.
In medium bowl, whisk oil and sugar together. Add eggs, one at a time and whisk to combine. Add vanilla extract and whisk to combine. Add in all the dry ingredients and whisk together until mixture turns to a thick batter. Spread into greased 9x9 pan.
Bake brownies in preheated until almost done baking, about 20-25 minutes. In the meantime, make the pecan pie topping.
Combine pecan pie ingredients - EXCEPT egg and vanilla extract - in a medium sauce pan and place over medium heat. Once butter has melted and mixture has begun to bubble, remove from heat. Add vanilla extract and whisk together. Let mixture cool for 5 minutes and then whisk in the egg.
Once the brownies are done, remove from oven (but keep oven on!) and pour pecan pie topping over the top. Spread to edges so it's in one even layer. Bake for an additional 15-20 minutes or until the topping has bubbled up and slightly browned.
Remove from oven and let them cool completely before cutting, about 2 hours.