Preheat the oven to 160°C (approximately 325°F). Grease the pan with vegetable oil.
Chop the chocolate and melt with the espresso over a hot water bath. Mix the melted chocolate with the canola oil.
Separate the eggs. Beat the egg whites with the salt until stiff. Stir in the sugar. Beat the egg yolks into the chocolate mixture. Add the orange zest and nutmeg.
Mix the grated coconut, flour and cream of tartar. Loosely fold the flour mixture and egg whites into the chocolate mixture.
Pour the batter into the pan and bake for about 35 minutes. Remove from the oven, let cool and serve.