Preparation of Dry Ingredients: In a medium-sized bowl, thoroughly whisk together the all-purpose flour, baking powder, and salt. Once combined, set this bowl aside.

Creaming Sugar and Oil: Utilize either a stand mixer or a large mixing bowl to blend the granulated sugar and canola oil. Mix at a medium to high speed until the mixture is smooth and well-combined.

Incorporation of Cocoa Powder and Espresso Powder: Add the unsweetened cocoa powder and, if desired, the espresso powder to the sugar and oil mixture. Continue mixing until these ingredients are fully integrated, ensuring to periodically scrape down the sides of the bowl to incorporate all ingredients evenly.

Adding Eggs and Vanilla Extract: Introduce the vanilla extract to the mixture. Then, add the eggs one at a time, beating the mixture thoroughly after each addition until it achieves a smooth and homogenous texture.

Combining Dry and Wet Mixtures: Gradually incorporate the previously set aside flour mixture into the wet ingredients. This should be done in two to three additions, mixing on a low speed to just combine the ingredients. Be sure to scrape down the sides of the bowl after each addition to ensure a consistent dough.

Chilling the Dough: Transfer the cookie dough to an airtight container or cover the mixing bowl with plastic wrap. Refrigerate the dough for a minimum of four hours, or until it is firm enough to be handled. As an alternative, the dough may be chilled in the freezer for at least one hour.

Preheating and Preparation for Baking: Preheat the oven to 350℉ (175℃). Prepare a large baking sheet by lining it with parchment paper or a silicone baking mat.

Rolling in Powdered Sugar: Place the powdered sugar into a small, shallow bowl. Scoop approximately 1 ½ tablespoons of the chilled cookie dough and roll it into balls using your hands. Then, gently roll these dough balls in the powdered sugar, ensuring they are fully coated, and place them on the prepared baking sheet, spaced about 2 inches apart.

Baking the Cookies: Bake the cookies in the preheated oven for 10 to 12 minutes. It is critical to avoid overbaking to ensure the cookies retain their desired texture.

Cooling: After baking, let the cookies rest on the baking sheet for 2 to 3 minutes before transferring them to a wire rack to cool completely.

Storage: Once cooled, the cookies can be stacked and stored appropriately.