In a thick-bottomed dish, put the broken into small pieces dark chocolate to melt. Successively, add the condensed milk, butter and salt, which need to melt gradually over low heat. Beat the flour with a little water and add the sugar. Add it to the other mixture, while beating constantly.
Put the pistachios in a plastic bag and crush with a rolling pin. Add these crushed nuts to the chocolate mixture. Pour the mixture into an aluminum tray with dimensions a bit over 8″ (20 cm) per side.
Smooth out the mixture and put it to bake in a low oven for about 45 minutes. Cut into pieces and serve it.