Preheat oven to 325F. Adjust an oven rack to a lower-middle position.

Line an 8 inch square metal baking pan with foil or parchment paper.

Put chocolates, butter, and instant coffee/espresso in a microwave safe bowl. Microwave on high, stirring every 30 seconds, until chocolate is almost melted. Remove from microwave, and stir to melt remaining bits of chocolate. Alternatively, you can melt the choco/butter/coffee combo over a pan of simmering water: put a heat-proof bowl over a pan of simmering water, making sure the bottom of the bowl doesn't touch the water, and stir until everything is melted. Remove from heat.

Whisk in sugar, salt, baking powder, and extracts into the chocolate mixture. Then whisk in the eggs, one at a time, mixing each one completely before adding the next one. After adding the eggs, whisk the mixture until smooth and glossy. Add flour; whisk until just incorporated. Do not overmix. Stir in the nuts.

Pour batter into the prepared pan; flatten the top with a spatula. Bake until a toothpick poked into the center comes out with wet crumbs, 55 to 65 minutes. (If your oven is notorious for overheating, start checking around 45 minutes.)

Cool brownies in pan on a wire rack. When cool enough to handle, use the foil or parchment to pull the brownies from pan. Completely cool brownies on rack, at least 3 hours. Be patient, or the brownies won't cut into nice squares and you'll have a mess on hand. ... Cut and enjoy!!!