Line a 16.5 x 16.5 cm (6.5 x 6.5 inch) baking pan with parchment paper.

In a bowl, add eggs, vanilla extract, and coffee essence. Beat for 1 minute.

In a pot, melt the unsalted butter over low heat.

Once the butter is melted, add muscovado sugar, granulated sugar, and salt. Stir for about 1 minute, then remove from heat.

Pour the warm butter and sugar mixture into the beaten eggs and whisk for about 1 minute.

Sift in the baking powder, flour, and cocoa powder. Mix with a spatula until the flour is fully incorporated.

Fold in the chocolate chips.

Pour the brownie batter into the prepared pan and spread evenly.

Bake in a preheated oven at 170°C (338°F) for 18 minutes.

While the brownie bakes, chop the pecans. You can use a knife or a food processor for a finer chop.

In a separate bowl, combine honey (or maple syrup), muscovado sugar, salt, egg, melted butter, and optional rum. Whisk for 1 minute until well combined.

Add the chopped pecans to the topping mixture and stir until the nuts are completely coated.

Remove the partially baked brownie from the oven. Pour the pecan topping mixture over the hot brownie and spread it evenly to the edges.

Return to the oven and bake for another 20 minutes at 170°C (338°F), or until the pecan layer is golden brown.

Remove from the oven and let it cool completely. For best results, cool for at least 2 hours in the refrigerator.

Once cooled, cut the brownie into 9 or 16 pieces.

Store the brownies at room temperature for up to 4 days, in the refrigerator for up to 10 days, or freeze for up to 3 months.