Preheat the oven to 180°C/355F. Grease and line the 8x8 or 9x9 square tin.
Melt the butter in the microwave. Add in the sugar, and whisk together, pop the mixture back into the microwave for 30 seconds on high. Then whisk furiously, repeat the step 3 times, until you have completely dissolved the sugar and have a thick butter mixture.
200 grams butter, 400 grams white granulated sugar
Dissolve the coffee and salt and 1-2 tablespoons of warm water, add to the butter mixture and whisk through. (If not adding the coffee granules, simply toss the salt into the butter mixture and carry on.)
2 teaspoon instant coffee, 1-2 tablespoons hot water, ½ teaspoon table salt
Add in the vanilla extract, add in the eggs one at a time and whisk furiously and vigorously for 2 minutes are each addition. Or, use a handheld electric beater and beat for 3 minutes until the mixture has lightened in colour and looks a bit frothy. I highly recommend taking the handheld electric beater approach. This makes a really nice crackly top.
1 teaspoon vanilla extract, 4 eggs
Mix in the flour and cocoa powder using a silicone spatula or wooden spoon until just mixed. Pour into the prepared baking dish and bake for 25-30 minutes. Allow the brownie to cool completely to allow it to set before slicing.
110 grams plain flour, 80 grams unsweetened cocoa powder