"They all want to find out what our secret recipe was to get it passed."
"Will you show me the rest of your secret recipe?"
It was a secret recipe that I thought died with her.
No one has ever discovered the secret recipe for army tea.
They must have some secret recipe that they've had the good sense to keep on using.
Each establishment usually had a claim to some kind of "secret recipe."
One day you must pass on your secret recipe.
To this day, the secret recipe is only known to the Twomey family.
His wine came from a secret recipe, with all that entails.
"But if you're lucky, maybe I'll share my secret recipe with you."