11y can make pretty much anything following a recipe. She goes in phases, and its normally holidays, but she likes to chose a recipe, we order the stuff to arrive and then gets stuck in. She is very much like me though - likes to cook savoury/main courses rather than baking.
I don't really have to do much to help, but always stick around in next room just in case.
I have 100s of cookbooks. DD just choses from any of them - Jamie Oliver and Hairy Bikers are written pretty clearly and easy to follow.
DD 11 can make several pasta dishes, risotto, fajita's and quesadillas etc. DD also loves to bake and regularly makes cupcakes, cookies and bread. Each week she looks through cookery books chooses a recipe and the following week she makes it. Risotto is easy to do as most of it is stiring. Pick meals with only a few steps to them. My DD refuses to let me help her cook anymore opting to learn herself which has resulted in some very interesting meals
My pre-teen 9 year old can't cook anything independently but makes a good sous chef, stirring pans, cutting mushrooms, onions etc. I expect that in the next couple of years her skills will increase.
My teen 14 year old can make a reasonable attempt at an omelette under supervision, and can make beans on toast. However DD1 is ?dyspraxic? and is generally unsafe in the kitchen despite many many attempts at training / supervision. She will burn herself stirring things, hold things unsafely when cutting etc. She is slowly getting more safe, though (I think). This is a long term project aiming for skills before she starts 6th form.
How many things can your pre-teen dc's cook? DD 11 can make pancakes, scramble and fry eggs and make coffee and tea. We will be teaching her to do more now as she keeps asking and we think she is ready.