Where can I find Mega burger bun in Grabs?

Mega burger bun can also be found in these cities:

Altach Appenzell Buchs Feldkirch Göfis Götzis Hohenems Koblach Laterns Mels Mäder Oberriet Schnifis Sulz Walenstadt Weiler Übersaxen

You can also find this in Grabs:

Semolina Porridge Cake Vanilla Sugar Jelly Ice Cream Desserts Meat Products Lemonades Instant Coffee Pumpkin Seed Roll Canned Meat