Custard is quite easy to make, except for the tricky bit at the end where you have to watch it like a hawk and stir continuously to prevent it curdling. I make custard frequently, as Simon is very keen on good stodgy British puddings*, washed down with rather more custard than is an elegant sufficiency.
Next, mix together 4 egg yolks, 3 tablespoons of sugar (vanilla flavoured if you've been reusing your vanilla pods frugally) and 2 teaspoons of cornflour. I most definitely stir these ingredients together, never whisk – the added air with whisking changes the flavour and mouthfeel of the custard. You may like the more moussy effect, but I find it a bit weird. The addition of cornflour is a cheat, by the way. It acts to help stabilise the mixture and give you more leeway before it curdles. I can make beautiful custard without the cornflour, but it takes a little bit longer and I have to be more careful about the temperature. Our stove has solid plates which heat up and cool down slowly, so I don't have the control I would like over the temperature and have to use a work around. I could use a bain marie, but that's a bit more trouble and the thickening takes even longer.
*Actually, Simon is keen on most puddings - and the true meaning of "elegant sufficiency" is "not enough". Simon