This episode is about a picnic. There are picnic hampers that are full of bugs.
Mama Baker does not have any berries.
However as the characters are meant to gathering berries they are actually puting anything into the basket, including twigs and leaves.
It seems like the basket might be a magic hamper that turns the bits into berries.
The song comes in the middle of the episode here: Bouncy Oven is happy to be cooking.
Then a flood of pies erupts out of the oven. Everyone is covered in pie juice that looks like blood.
The episode ends with the bugs still crawling over the ground.