Preheat your oven to 350°F (175°C) and grease a 9-inch round cake pan.

In a large mixing bowl, combine flour, sugar, baking powder, espresso powder, and salt. In another bowl, cream the butter and mix in the eggs and milk before adding the dry ingredients.

For the streusel, mix brown sugar, cinnamon, and nuts; then add melted butter until crumbly.

Pour half of the batter into the pan, sprinkle with half the streusel, add the remaining batter, and top with the rest of the streusel.

Bake for 30-35 minutes until golden and a toothpick comes out clean.

Let cool for 10 minutes in the pan before transferring to a wire rack.

Slice and serve with optional powdered sugar, ice cream, or whipped cream.