My method seems to work everytime;
It's an equal measure recipe. The same volume of eggs, plain flour (sifted) and milk.
I use a ramekin dish for us (there's only 2 of us), but you can scale up very easily to a mug etc.
Basically as many eggs as it takes to get to a level of your jug/cup etc (remember the level you filled to), pour these into a bowl, add plain flour to the same measurer you used for the eggs, fill with the flour up to the same level that the eggs reached, sift this into the bowl with the eggs. Do the same with the milk and add to the bowl, whisk until smooth.
Make sure you're using oil that does not burn (I use goosefat) and heat in in the baking trays for as long as possible. I then find it works if 2 of you can do the pouring of the mix into your oven trays, as speed means that the oven and oil have less time to cool down any.
Just done this this afternoon for our Sunday roast and they rose a treat, yummy!!!!