Preheat the oven to 180°C/355°F. Grease and line a regular or standard loaf pan with parchment or baking paper, making sure to leave an overhang for easy removal of the loaf.
Add the coffee to the hot water, stir, and allow it to cool.
2 tablespoons instant coffee, 180 mL hot water
In a large bowl, beat together the butter, brown and white sugar until well combined. This will take about 2-3 minutes using an electric hand mixer.
165 grams light brown sugar, 150 grams white granulated sugar, 113 grams butter
Add in the eggs and vanilla and beat until well combined, light, fluffy, and smooth. About 2-3 minutes using an electric mixer.
2 eggs, 2 teaspoon vanilla extract
Pour in the cooled coffee mixture.
Add in the walnuts, flour, salt, and baking powder. Mix until combined.
330 grams plain flour, 3 teaspoon baking powder, ½ teaspoon table salt, 95 grams walnuts
Pour into the loaf tin. Bake for 50-60 minutes or until a cake tester or toothpick comes out mostly clean from the center of the loaf.
Allow the cake to cool in the tin for 15 minutes before placing it on a cooling rack to cool completely.
Combine 1 tablespoon of water/ milk with the ½ teaspoon of coffee, stir, and set aside. In a large mixing bowl, combine the room-temperature cream cheese and butter. Beat with an electric hand mixer until smooth and combined. This will take about 3-5 minutes.
1 tablespoon water/milk, ½ teaspoon instant coffee, 60 grams cream cheese, 30 grams butter
Add in the brown sugar and beat until well combined and dissolved. This will take about 3 to 5 minutes.
3 tablespoon light brown sugar
Add in the coffee milk and mix through. Then add 10 tablespoon of the icing sugar and mix. Continue adding the icing sugar one tablespoon at a time until the frosting is a nice spreadable consistency.
13 tablespoon icing sugar
Spread the icing over the top of the cake. Slice and serve.