Preheat oven to 275 degrees.
Grease and flour a large bundt pan (or spray with baker’s spray)
Cream together the butter, brown sugar and granulated sugar in a stand mixer, starting on low speed and then on high speed until the mixture is light and fluffy.
Add the eggs and vanilla to the butter mixture and mix on medium speed until the eggs are just incorporated. Do not over mix.
Sift the flour, baking powder and salt together in a small bowl.
Gradually add the flour mixture to the butter mixture on low speed until just combined.
Add the sour cream and buttermilk and mix until just combined.
Add the espresso and mix until just combined.
Add the chocolate chips until just combined.
Scoop the cake mixture into a large, prepared bunt pan. Fill the pan 3/4 full. If your bundt pan is not big enough, scoop the remaining batter into prepared muffin tins or a small loaf pan.
Place in the oven and bake for 1 hour and 45 minutes to 2 hours until a knife inserted comes out clean.
Let the cake cool, then remove from the pan and garnish with confectioners sugar before serving.