If you have OFB you can select to Make One... Group Meal on the stove or fridge. The sim will then cook a group meal that will go into their inventory. This is the important part - the meal has to be unserved so it has to be done via the OFB Make One... menu. You can then use the meal cooked at home to enter the contest. Once the unserved meal is in the sim's inventory you can also transfer it between sims. That's how my sim with 1 cooking point won a contest - she served a meal cooked by her daughter, who had 9 cooking skill points.
O O I never thought of that! Thanks