2 cups all purpose flour
1 tsp baking powder
1/2 tsp baking soda
1/4 tsp salt
1/3 cup butter, room temperature
1 cup sugar
1 large egg
2 tsp vanilla extract
3/4 cup milk
1 1/2 tbsp instant coffee
1 tbsp brown sugar
2 tbsp warm water
coarse sugar, for topping
Preheat oven to 350F. Lightly grease a 9×5-inch loaf pan.
In a medium bowl, whisk together flour, baking powder, baking soda and salt.
In a large bowl, cream together the butter and sugar until light and fluffy. Beat in egg and vanilla extract. Stir in half of the dry ingredients, followed by the milk. Stir in the remaining dry ingredients, mixing only until no streaks of flour remain.
In a small bowl, whisk together instant coffee and brown sugar with warm water. Stir to dissolve the coffee. Transfer about half of the vanilla batter into the small bowl and stir until batter is a uniform coffee color.
Add dollops of vanilla and coffee batters to prepared pan (making an almost polka-dot pattern) and run a butter knife through the pan once or twice to swirl the two colors gently together.
Bake for 40-45 minutes, or until a toothpick inserted into the center comes out clean or with only a few moist crumbs attached. Allow to cool in the pan for 5 minutes, then turn out onto a wire rack to cool completely.