actually, this thing is explainable.
basic oven has 19 recipes available to all players who are not higher than level 12.
drink mixer only has 10 such recipes.
(except recipes shorter than 30 minutes)
and so far they used them all for flash goals and for long side goals
so, if they use other dishes, they will have to higher level requirements for goals, and ppl will not get goals when they reach level 12.