In a medium bowl, whisk together the flour, sugar, cocoa powder, baking soda, sea salt, and espresso powder. Set aside.
In a large mixing bowl, combine the melted butter, canola oil, eggs, sour cream, milk, and vanilla extract. Whisk until the mixture is smooth and well blended.
Gradually add the dry ingredients to the wet ingredients, stirring until fully incorporated. Fold in the mini chocolate chips, ensuring they are evenly distributed throughout the batter.
Pour the batter into the prepared Bundt pan. Use a spatula to smooth the top, then gently tap the pan on the counter to release any trapped air bubbles.
Bake for 35–45 minutes, or until a toothpick inserted in the center comes out clean or with a few moist crumbs. Larger Bundt pans may require a slightly shorter baking time.
Place the Bundt pan on a wire cooling rack and allow the cake to cool to room temperature. Once cooled, carefully run a knife around the edges and center of the cake to loosen it from the pan. Place a wire rack on top of the Bundt pan, then carefully invert the pan, allowing the cake to release onto the rack. Let the cake cool completely.