Preheat the oven to 350°F (175°C) and grease a 9-inch round cake pan.
Whisk together flour, baking powder, baking soda, salt, and espresso powder.
Beat butter and sugar in a bowl until fluffy. Add eggs and vanilla, mixing well.
Add dry ingredients alternately with sour cream, then fold in lemon zest and juice.
Pour batter into the prepared pan and smooth the top.
Bake for 35-40 minutes or until a toothpick comes out clean.
Let the cake cool in the pan for 10 minutes, then transfer to a cooling rack.
To make the glaze, whisk powdered sugar, lemon juice, and espresso powder until smooth.
Drizzle the glaze over the cooled cake.