Preheat oven to 350℉ and grease or line a loaf pan with parchment paper.
Add melted butter, oil, cocoa powder, and espresso powder to a bowl. Mix to combine.
Add the sugar and mix until combined.
Add the eggs, baking soda, and salt. Whisk until well combined. Be sure to scrape down the bottom and sides of the bowl.
Mix in the milk, sour cream, and vanilla until fully incorporated.
Mix in the flour until combined.
Pour batter into a prepared loaf pan and bake for 62 - 68 minutes or until a toothpick inserted into the center comes out clean or with a few moist crumbs.
Allow to cool in the pan for a few minutes before removing and placing on a wire cooling rack to cool. If you lined the pan with parchment paper, you'll want to remove that from the loaf as well.
Brown Butter Espresso Hot Fudge
Add butter to a light colored saucepan. Cook, stirring occasionally, over medium-low heat until butter melts and begins to brown.
Once you notice plenty of golden brown bits in the bottom of the pot, whisk continuously as you pour in the cream.
Add the sugar, cocoa powder, salt, and espresso powder. Stir frequently as you bring the mixture to a simmer. Once simmering, stir continuously for 2-3 minutes until thickened.
Remove from heat, add vanilla extract and stir to combine.
Pour the hot fudge over individual slices of cake and enjoy. This cake is also wonderful served with a scoop of vanilla ice cream.
Notes
Room Temperature Ingredients - having the ingredients at room temperature allows everything to mix and emulsify well, resulting in a smooth and cohesive cake batter and a more consistent cake texture.