Unfortunately cake is usually called gebak or taart. There isn't a directly translatable word for cake. It may also be handy to know that "Hartige taart" can be used to refer to quiche.
The same word for "cake" and "pie"? Isn't there another Dutch word for "cake"? I seem to remember something we had for breakfast in the Netherlands (many years ago now).. It was called "Friesland Cake" in English, and I am pretty sure the Dutch didn't call it a "taart".
We also use the loan word "cake" in Dutch, but only to refer to a specific type: no cream or filling, minimal topping, usually loaf-shaped. What you would call a pound cake in English, I believe.
Do an image search for "cake recept" to get an idea.
The cake you're referring to might have been "Fries suikerbrood".
So I guess koek doesn't mean cake then? lol. Have had a Dutch food called "boterkoek" which I was told means "butter cake". Lekker!!