It is not hard to make chocolate glaze with quality semi sweet or bittersweet chocolate, be it in bulk, squares or in chocolate chip form. All you have to do is chop it into small pieces, slightly melt it over very low heat, [the safest is in the top of a double boiler] and add water or milk to it for pouring consistency. It is a little more challenging to make it from cocoa. However, the same principles apply; use unsalted butter and good quality, unsweetened cocoa. This way your cocoa based chocolate glaze will be rich and chocolaty. You may add liquor to enhance the flavour, but I would not add vanilla extract to a cocoa-based glaze, because the vanilla tends to overpower the cocoa. To cover an entire cake, double the amounts.
COCOA CHOCOLATE GLAZE
4 Tbsp unsalted butter6 Tbsp unsweetened cocoa
6 Tbsp water
4 Tbsp sugar
• Melt the butter in a small saucepan over low heat.
• Stir in the cocoa and the cold water.
• Cook, stirring constantly, until mixture thickens. Do not boil.
• Remove from heat.
• Gradually add the sugar, beating it with a whisk until smooth.
• Add additional warm water, but only 1/2 teaspoon at a time, until the desired consistency.
• Pour glaze over top of cake.
• Let the glaze freely drizzle down the sides.