Make sure all your tools are clean and disinfected.

Bring a pan with a little water to the boil. Warm your beaker to about 70 °C, then gently stir in the decyl glucoside, coco glucoside and cocamidopropyl betaine. Go slowly, or you'll end up with a bowl of foam.

Meanwhile, make a paste of phase B: stir the glycerine, xanthan gum and niacinamide together in a small bowl until there are no dry lumps left.

Stir in the paste from phase B. Your cream will slowly become a bit thicker.

Check the pH; it should be around 5.5. This pH is not only the most comfortable for your skin, it also lets the preservative work at its best. Use a 10% citric acid solution (in demineralised water) to lower the pH, or a 10% baking soda solution (in demineralised water) to raise it. Always add a maximum of 1 drop at a time, stir well and wait at least 1 minute before measuring again. As a guide: in 100 grams of mixture, 1 drop changes the pH by about 0.1 to 0.15 points on average. Work carefully and avoid over-adjusting.

Pour your cleanser into a pump bottle and give it a nice label.