That's the cherry on top
A dessert topping
An extra good feature that completes something
Eat humble pie
Admit you were wrong or humbled
Eat a pie made of humble ingredients
Full of beans
Energetic and lively
Full of literal beans
A piece of cake
A slice of cake
Something very easy
Spice things up
Add spices to food
Make more exciting
Too many cooks spoil the broth
A soup gets too salty when too many cooks are involved
Having many people working on something can ruin it
Butter someone up
To physically butter someone
To flatter someone to gain favor
In a pickle
In trouble
In a brine jar
The apple doesn't fall far from the tree
Children resemble parents
Apples grow underneath trees
Go nuts
Become crazy or excited
Eat nuts
Cool as a cucumber
Literally cool as a cucumber
Very calm and composed
Spill the beans
To reveal a secret
To spill a pot of beans on the floor
Bring home the bacon
To cook bacon for everyone
To earn money to support a family
The icing on the cake
The frosting that goes on baked goods
An extra good feature that makes something even better
Not worth a hill of beans
Not tasty
Not worth much
Take with a grain of salt
Add salt to food
Be skeptical about something
Sour grapes
Pretending to despise something you can't have
Grapes that are sour to taste
Bite off more than you can chew
To physically bite too much food at once
To take on a task that is more difficult than you can handle
Couch potato
A lazy person
A potato on a couch
Food for thought
Something to think about
Actual food to eat