Preheat the oven to 180°C (356°F).
Grate the zucchinis without squeezing out the water.
Melt the dark chocolate in a saucepan over a bain-marie or in the microwave. Stir until smooth and well combined.
Whisk the eggs and sugar until light and fluffy.
Add the melted chocolate and mix well.
Sift in the flour, instant coffee, and salt. Add the coarsely chopped pecans, grated zucchini, and chocolate chips. Mix until evenly combined.
Line the pan with parchment paper. I used a square pan, but a round one will work just as well.
Pour the batter into the pan and smooth the top. Sprinkle with some chocolate chips, but this is optional.
Bake on the middle rack of the oven for about 25 minutes.
Check for doneness by inserting a skewer into the brownie; it should come out clean.
Turn out onto a wire rack and let cool before cutting.
Enjoy warm or cold, according to your preference.