1.Preheat oven to 350°F and spray a 9x5-inch loaf pan with baking spray.
2.In a medium or large bowl, whisk together flour, cocoa powder, sugar, baking powder, and salt. Add eggs and 1 teaspoon vanilla and whisk to combine. Add vegetable oil, maple syrup, milk, and 2 tablespoons instant coffee. Whisk until completely incorporated and instant coffee has dissolved.
3.Pour batter into the prepared pan and bake for 50 minutes, or until a toothpick inserted into the center of the cake comes out clean. (A few crumbs are okay!) Let the cake cool in the pan.
4.To make the glaze, dissolve 1/2 tablespoon instant coffee in hot water. Whisk together coffee, 1/4 teaspoon vanilla, and powdered sugar until completely incorporated. Glaze will be thick but should be easy to drizzle with a spoon. (If not, add 1/2 teaspoon water until desired consistency is reached.) Drizzle glaze over cake and let it set up for 15 to 20 minutes. Cut into slices to serve.