In the bowl of a stand mixer fitted with the paddle attachment, combine the room temperature butter and sugar and beat on medium speed until light and fluffy.
Add the eggs, one at a time, beating well after each addition. Add the corn syrup, followed by the vanilla and espresso. Mix thoroughly then add the melted Bahibé 46% chocolate.
Combine the dry ingredients and add them in two parts. Finish by adding the chopped nuts and Bahibé 46% chocolate. Remove from mixer and stir with a spatula to ensure at homogenous batter.
Pour into a buttered 9x13” pan and bake at 350ºF for 45-50 minutes, or until a skewer placed in the center comes out clean. Cool completely before cutting into portions.
Notes
For a smaller batch, cut the recipe in half and use an 8"x8" pan (or 9"x9", but it would not be as thick, so you may reduce the bake time)