How to beat one or two egg yolks? Many sauces and pastries call for beaten yolks. You need to beat yolks well, till they are thick again and are lemon-colored, so using mixer is a must. 
But if you need only one or two egg yolks, regular mixers are too big for the task. What I'm currently using is a battery-driven micro mixer, and it is not powerful enough and eats up batteries fast.
Can anybody suggest a good solution to the problem?
Using a mixer is not "a must". You should be able to whisk 1-2 egg yolks together quite easily which a whisk and some elbow grease. How do you think we beat egg yolks for the centuries prior to electricity?