Preheat the oven to 350 F (170 C). Line a 9 x 5 loaf pan with parchment paper, leaving a bit of overhang on two sides.
In a large bowl, whisk the flour, cocoa powder, baking soda, baking powder, espresso powder and salt together until well combined. Set aside.
1½ cups (180 g) all purpose flour, ½ cup (40 g) unsweetened cooca powder, 1 teaspoon baking soda, ½ teaspoon baking powder, 1 teaspoon espresso powder, ¼ teaspoon salt
In a large mixing bowl, whisk the granulated sugar, light brown sugar and eggs until smooth and well combined. Then whisk in the oil, buttermilk and vanilla extract until smooth and well combined.
1 cup (200 g) granulated sugar, ¼ cup (50 g) light brown sugar, 2 large eggs, room temperature, ½ cup (120 ml) oil , 2 teaspoons (10 ml) vanilla extract , ¾ cup (180 ml) buttermilk, room temperature
Sift and then whisk the dry ingredients into the wet until just combined. When the dry ingredients are mostly combined, whisk in the warm water or coffee. Fold in the chocolate chips. Reserve ¼ cup for topping the cake.
¼ cup (60 ml) very warm coffee or water, 1 cup (170 g) chocolate chips, divided
Evenly pour the chocolate cake batter into the prepared pan. Using the back of a spoon or the side of a flexible spatula to smooth out the top of the chocolate cake batter. Top with the remaining ¼ cup chocolate chips.
Bake the double chocolate loaf cake for 50 - 60 minutes or until a toothpick inserted into the center of the chocolate loaf comes out with a few moist crumbs.
Cool the cake in the loaf pan for 10 - 15 minutes. Use the parchment sling to lift the bread out of the pan. If needed, use a butter knife to loosen any cake bread pieces from the pan. Cool completely before slicing the chocolate loaf cake. Enjoy as is, with your favorite fresh fruit and freshly whipped cream, topped with a silky chocolate ganache glaze or with creamy frosting.