Preheat the oven to 375°F. Lightly spray a donut baking tray with baking spray.
In a large bowl, sift in the flour, cocoa powder, baking soda and salt. Whisk to blend.
In a microwave safe medium bowl (or 500 ml measuring cup), combine the oil and chopped chocolate. Microwave for 25 second bursts, stirring well each time just until the chocolate is melted. Keep an eye on it as chocolate burns and seizes very easily.
Mix in the plant-based milk, vinegar, vanilla and instant coffee/espresso powder if using. Whisk well until the coffee/espresso is dissolved. Pour into the dry ingredients and, mixing with a spatula or large spoon, mix until just blended taking care not to over-mix.
Spoon the batter into a large piping bag or large zip-lock bag (cutting a corner out once filled and closed), and pipe the batter into the donut cavities. Bake for 12-14 minutes, or until a toothpick inserted comes out clean. Let cool for 10 minutes before inverting on a cooling rack and dipping in the ganache.