The grocery shop chain "Best Market" got together everything, what a Ukrainian can need: huge choice of fish, preserves, sauces, sweets, drinks from the Ukraine, even beers. You will find there Ukrainian crisps, sunflower's seeds, halvah and marshmallows. In view of the fact that the import of meat and dairy from the Ukraine to UE is forbidden, some Polish products are offered as a substitutes. The choice of Ukrainian goods is completed with famous, Georgian lemonades, condensed milk from Germany and Polish lard. 

Ukrainians make up the majority of employees in the shops. 
On the shop's website you can not only buy things, but also read about some Ukrainian traditions in Polish language. On the website there are also posted some job offers. 
The shop's website:  https://best-market.pl/ 

Shops in Warsaw:
Jana Pawła II 52/54 street
phone number:  516 700 805
email: warszawa@best-market.pl
10.00 a.m - 10.00 p.m

Męcińska 30, paw 22/24 street
phone number: 513 592 528
email: warszawa-wiatraczna@best-market.pl  
10.00 a.m - 10.00 p.m