Mittens are great... 2 nights work & some sewing up and you have a present sorted. Both pairs are made with Cleckheaton Country 8 ply. The light green pair are done on 3.75mm needles and the mauve pair are on 4mm needles. All the knitting is done, but I need to finish sewing up the other green mitten and both of the mauve ones.
The beauty of this pattern is that it is simple and scalable - that is - just use varied weights of wool and the appropriate needles to get bigger or smaller sizes. For a 3-4yr old, use 8ply + 3.75mm, slightly older use 4mm etc. It's a 1940s Patons pattern called Cezanne from the Patons Knitting Book R.10 (p10-11). This book has lots of lovely gloves, mitten and hat patterns. Unfortunately my copy of the book is missing the front & back covers (which does include some of the pattern info).