When it boils, remove from the heat and add chopped dark chocolate. Stir slowly to melt and add the strained gelatin, stir until smooth and strain. Store in a airtight container in the fridge over night. When you’re about to use it, warm the chocolate mirror glaze to the temperature around 110°F (44°C) before using it. If you do get a a lot of air bubbles in the glaze, strain it through a fine mesh strainer before using, otherwise the tiny bubbles will show on the finished cake.