We have two kids, ds9 & dd10.
I have a very strict rule that they do not turn on the oven or stove. Period. Not even with adult supervision. We do it. They can use the microwave, but its my rule that they do not turn on the oven/stove. That's my rule!
Well, recently they started helping me make cakes and other baked goodies. They can make a cake from a box, and, after a few tries under supervision, I let them make the cake without our supervision. That is, they can mix the ingredients without supervision, they can use the cake mixer with adult supervision, but they do NOT turn on the oven.
Tonight they asked if they could make a cake. I restated the rules to them--mix the ingredients, then use the mixer with either dh or me supervising, but I explicity told them NOT to turn on the oven. We would do that. Well, I went into the kitchen and found the oven turned on, and practically up to broiling--500 degrees! I wondered why it was getting so warm in the house! I asked them why they had turned on the oven when told not to. They both grinned and acted like it was a big joke, and, of course, each blamed the other. I turned off the oven and threw away the cake batter. I also threw away several boxes of cake mix and frosting. They immediately started crying--they were looking forward to the cake. Well, I said they had broken my rules, so they could not have the cake. I also threw away the remaining box mixes. I was afraid they would decide to bake another cake when we were not supervising and could not be trusted not to turn on the oven.
When they were younger I removed the knobs from the gas stove so they couldn't play with it. But I really think they're old enough now to understand and obey rules. DH thinks I'm being too harsh, he says I should not have thrown away the cake mix, perhaps kept it and baked it tomorrow. I felt I had to make my point known in no uncertain terms. Accidents happen in the kitchen frequently. Kids need adult supervision. If they don't follow the rules, they can't play the game!
I have a very strict rule that they do not turn on the oven or stove. Period. Not even with adult supervision. We do it. They can use the microwave, but its my rule that they do not turn on the oven/stove. That's my rule!
Well, recently they started helping me make cakes and other baked goodies. They can make a cake from a box, and, after a few tries under supervision, I let them make the cake without our supervision. That is, they can mix the ingredients without supervision, they can use the cake mixer with adult supervision, but they do NOT turn on the oven.
Tonight they asked if they could make a cake. I restated the rules to them--mix the ingredients, then use the mixer with either dh or me supervising, but I explicity told them NOT to turn on the oven. We would do that. Well, I went into the kitchen and found the oven turned on, and practically up to broiling--500 degrees! I wondered why it was getting so warm in the house! I asked them why they had turned on the oven when told not to. They both grinned and acted like it was a big joke, and, of course, each blamed the other. I turned off the oven and threw away the cake batter. I also threw away several boxes of cake mix and frosting. They immediately started crying--they were looking forward to the cake. Well, I said they had broken my rules, so they could not have the cake. I also threw away the remaining box mixes. I was afraid they would decide to bake another cake when we were not supervising and could not be trusted not to turn on the oven.
When they were younger I removed the knobs from the gas stove so they couldn't play with it. But I really think they're old enough now to understand and obey rules. DH thinks I'm being too harsh, he says I should not have thrown away the cake mix, perhaps kept it and baked it tomorrow. I felt I had to make my point known in no uncertain terms. Accidents happen in the kitchen frequently. Kids need adult supervision. If they don't follow the rules, they can't play the game!
if i might, could i suggest an alternative? 

and disrespect going on behind your back and you need to nip that in the bud before the hormones are in full swing. I'm very matter-of-fact about it and I never make a threat I will not follow through on. After 21 years of child-rearing, my kids know that I mean business b/c I've meant business each and every time. On the flip side, our rules are very fair and are in place for a reason that is made clear to DDs. And, those rules evolve as the children grow. 8yo is not allowed to attempt ramen noodles alone yet, but she certainly helps with close supervision. My DH is very Mr. Monk-ish, the kids call him Mr. Safety Man, but even he understands the need for them to learn to manage tools, household appliances, etc. With proper supervision, they will learn and, it's a lot of fun cooking together. Your kids may see it as an arbitrary rule that doesn't make sense, and when you think about it, a 10yo is fully capable of turning on an oven without incident, so they don't see what the big deal is (and, really, it isn't). Putting the cakes in and out is a whole other ball of wax that they CAN see should be an issue, but not just pushing some buttons.
. We just have to hope for the best and move on. (my Dh is even a firefighter) I choose not to live my life on WHAT IF'S..you obviously have a different view on things.