What is a common mistake when making flan?

Two big mistakes that you might be making that are sabotaging your custard dessert endeavors are getting your dessert perfectly smooth in its texture, and failing to strain the flan mixture before cooking. Perhaps the biggest issue flan-makers face is getting their dessert perfectly smooth in its texture, and this may be due to overmixing it before cooking. Overmixing may cause your flan to become clumpy as rapid motions suffuse your mixture with air bubbles. Another oft-repeated mistake many home cooks make when endeavoring to tackle the jiggly, custard treat is in failing to strain the flan mixture before cooking. Doing so will help you to achieve a smooth texture by removing potential lumps. Both mistakes contribute to a less-than-ideal texture to your dessert.