No player may take actions between the time you announce you're activating Witch's Oven's ability and the time you sacrifice a creature. Notably, they can't try to remove or shrink the creature you'd like to bake.

Food is an artifact type. Even though it appears on some creatures, it's never a creature type.

Whatever you do, don't eat the delicious cards.

You can't sacrifice a Food to pay multiple costs. For example, you can't sacrifice a Food token to activate its own ability and also to activate Maraleaf Rider's ability.