Prospero

•On a platter of gold❎
•On a silver platter✅

•Half bread is better than none.❎
•Half a loaf is better than no bread.✅

•What is good for the goose is good for the gander.❎
•What is sauce for the goose is sauce for the gander.✅

•Make haste while the sun shines.❎
•Make hay while the sun shines.✅

•To be forewarned is to be forearmed.❎
•Forewarned is forearmed.✅

Idioms are fixed expressions.