In the FCC episode, when the two guys crash cars(one is eating peanut butter, the other guy chocolate), the Cop that comes(Officer Reeses lol) takes the peanut butter jar that has the chocolate bar in it, but it turns into a chocolate bar with peanut butter on it.
He probably just takes the chocolate out of the peanut butter jar. Where does the jar go? He could have set it on the hood of the car. I know this sounds impossibly futuristic, but it's actually possible.
Ried is right, I have seen this episode many times myself, he takes the peanut butter covered chocolate bar out of the peanut butter jar and puts the jar on the car hood before he takes a bite, when he takes a bite, it's a close up on his middle shot of him taking the bite with the hood out of view, in the next frame, you can clearly see the jar on the hood and the bar in his hand