Seving Delicious Mauritian food at Walthamstow Market. Operating only on Saturdays. Mauritian Chicken Bryani, Dhall Pouri, Roti, Napolitan, and Ice cold Alouda. Walthamstow Market in the London Borough of Waltham Forest, is the longest daily outdoor market in Europe. It occupies all but the last 100 metres of Walthamstow's High Street.