Where can I find Mega burger bun in Büetigen?

Mega burger bun can also be found in these cities:

Bern Biberist Biel Bienne Bremgarten bei Bern Brugg Derendingen Gerlafingen Grenchen Gümligen Hinterkappelen Ipsach Ittigen Kerzers Kirchberg Langendorf Lyss Moutier Murten Münchenbuchsee Neuenstadt Nidau Ostermundigen Solothurn Tavannes Tramelan Utzenstorf Worb Zollikofen Zuchwil

You can also find this in Büetigen:

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