Gateau is food cake in french
A birthday cake in French is 'un gâteau d'anniversaire'
gâteau
A banana cake is "un gâteau à la banane" in French.
Nope!
gâteau sucré
Yes, it is typically served on French tables.
Yes.
If you mean a slice of cake it is - tranche
gâteau basque.
acheter un gâteau
Gateau(Le) gâteau
"un gâteau parfait"