This is my favourite cast-on, it’s flexible and discreet, but strong enough to hold the shape of the piece you’re knitting. It does, however, allow the fabric to roll a bit, so I guess if that annoys you, it might not be the one for you!
Also definitely the fastest once you’ve got the knack of it, it looks a lot harder than it is!
Start with a good old slip knot…
Pull the tail-end of the yarn towards you, over your thumb, with the ball-end of the yarn over your forefinger, and your remaining fingers gently holding the wool below…
Pull your thumb back, towards the end of the needle. A loop will begin to form around your thumb…
Put the tip of the needle into the loop that has formed around your thumb, pointing in the same direction as your thumb…
Move your left hand back towards your right hand, along the length of the needle. Pull the wool around your forefinger across (from left-to-right, or anti-clockwise) around the needle…
Keep going…
Pull your thumb back over the tip of the needle, outside the loop you have made with the other end of the yarn…
Pull gently on the yarn with your left hand…
Tug gently…
And repeat!