Good pie's have butter!
Contractions are used sometimes. Here it is pies not pie's.
is "n-are" a contraction?
Yes, and it's an acceptable translation. Either "n-are" or "nu are" is OK; you might use the latter for emphasis: "O plăcintă NU are unt!" when arguing with someone who claims it does.
The word plăcintă IS NOT IN THE LIST !?!
In current Romanian articles is rarely used. Just for insisting or to solve a doubt.
"Plăcinta" is actually a typical pastry in Moldova and Romania. It's more Iike a flat bread, that can be both salty or sweet, usually filled with cheese (brînză de vacă și mărar) or jam or potatoes and they are pan-fried. Miss them...