Grease and flour or line a 9x5 (23x13cm) loaf pan.
Combine flour, baking powder, cinnamon, cocoa and salt in small bowl. Set aside.
In a large bowl, beat eggs, oil, and vanilla until smooth. Beat in sugar. Add flour mixture and beat until you no longer see lumps, about 1 minute. Pour into prepared pan.
Bake 40-50 minutes or until a toothpick inserted comes out clean. Center should read between 190F (88C) and 210F (99C.)
Cool in pan for 10 minutes; remove to wire rack to finish cooling. Cool completely before icing cake.
Chocolate Glaze
Sift together powdered sugar and cocoa in a medium bowl. Add milk one teaspoon at a time until smooth and glaze ribbons off of the spoon.
Drizzle on top of the cake and allow to drip off the sides. Serve or store after 15 minutes to allow glaze to harden.
Notes
Do not over bake. Chocolate cakes will dry out if cooked too long.You can substitute all-purpose flour with self-rising flour. Just omit the salt and baking powder from the recipe.The type of cocoa powder will change the color and flavor. Dutch processed cocoa will have a darker appearance and is ideal as it will give a moist rich flavor due to the fat content. If using a cocoa powder without any fat, you may wish to decrease the flour to 3/4 cup (112.5grams.) Fat-free cocoa powder absorbs a lot of moisture and can lead to a drier cake.