Preheat your oven to 350 degrees Fahrenheit.
Grease your loaf pan with a thin layer or spray of vegetable oil and then line it with parchment paper. Set aside.
In the bowl of a stand mixer whisk together the 1 1/2 cups of flour; 1 cup of sugar; 1/3 cup of cocoa powder; 1 tsp baking soda; 1/2 tsp salt and 1/2 tsp vanilla powder (if that is what you are using). Whisk together to combine well.
Next add to the flour mixture the 1/3 cup of vegetable oil; 1 tsp white vinegar and 1 cup of room temperature water (and if you are using vanilla extract, add that in now, 1 tsp).
Using the paddle attachment of your stand mixer, mix all of the ingredients together until well combined.
Toss your 1 cup frozen blueberries with the 1 tablespoon of reserved cocoa powder until well coated.
Gently fold the blueberries into your cake batter using a rubber spatula.
Pour your batter into the prepared loaf pan. Smooth out the top with your rubber spatula.
Bake your cake in the middle rack of your oven for 55 - 60 minutes or until a toothpick inserted into the center of your cake comes out clean.
When your cake is ready, allow it to cool for 5 minutes in the loaf pan until transferring it out onto a cooling rack.
Once your cake is completely cooled, prepare your glaze. Melt the 1 cup vegan chocolate chips, and 2 tbsp coconut oil using a double boiler and once melted and smooth, pour the glaze over the loaf pan.
Decorate the top of your cake with fresh blueberries if desired.