Preheat the oven to 350°F (175°C). Grease and line a 9×5-inch loaf pan with parchment paper.

Dissolve the instant coffee granules in 1 tbsp of hot water and set aside to cool slightly.

In a large mixing bowl, cream the butter and sugar together until light and fluffy.

Add eggs one at a time, beating well after each addition.

Stir in the dissolved coffee.

In a separate bowl, whisk together the flour, baking powder, and salt.

Gradually add the dry ingredients to the wet mixture, alternating with the milk. Mix just until combined.

Pour the batter into the prepared loaf pan and smooth the top.

Bake for 50–55 minutes, or until a toothpick inserted in the center comes out clean.

Let the cake cool in the pan for 10 minutes, then transfer to a wire rack to cool completely.

For the glaze, mix powdered sugar, brewed coffee, and vanilla until smooth. Drizzle over the cooled cake.