Where can I find Mega burger bun in Büron?

Mega burger bun can also be found in these cities:

Aarau Bremgarten Buchrain Buchs Ebikon Egolzwil Emmen Fahrwangen Gränichen Hitzkirch Huttwil Lenzburg Lostorf Lucerne Malters Menziken Muri Oberkirch Oftringen Olten Rain Reiden Reinach Rothrist Ruswil Schöftland Schönenwerd Sempach Seon Suhr Sursee Unterentfelden Urswil Wohlen Wolhusen Zell Zofingen

You can also find this in Büron:

Pudding Decorative Sugar Three-Grain Bread Cereals Delicatessen Sausage Spice Pastes Mashed Potatoes Raisin Roll Canned Sausage