In a separate large bowl, beat the butter with both sugars until fluffy and light. Add the eggs one at a time, mixing gently, then stir in the vanilla extract. In another small bowl, combine the milk and sour cream until smooth.

In a bowl, mix the flour, baking powder, and baking soda.

Now, gently fold the flour mixture into the butter mixture in parts, alternating with the milk-sour cream mixture, starting and ending with the flour. Mix only until everything comes together to keep the loaf soft and tender.

Toss the chocolate chips in some flour and fold them into the batter, saving a few to sprinkle on top for a pretty, chocolatey finish.

Pour the batter into the prepared pan, smooth the surface with a spatula, and tap the pan lightly on the counter to release any air bubbles.

Bake for about 55–60 minutes, checking with a toothpick in the center, it should come out with just a few crumbs clinging. Let the loaf cool in the pan for a few minutes, then lift it out using the parchment and place on a wire rack to cool completely.

For the ganache, put the chopped chocolate in a bowl. Heat the cream just until small bubbles appear, then pour it over the chocolate. Give it a short pause, then stir softly until it turns velvety and completely smooth. Add the vanilla extract and a pinch of espresso powder if you want a subtle depth of flavor.

Spread the ganache over the cooled loaf and let it set for a few minutes. For a neat, bakery-style look, pour in one direction and gently nudge with the back of a spoon. Slice and enjoy!