First, preheat the oven at 180 c. Then ,add water in the pot and find another pot put on the pot and cut the chocolate bar into small pieces make it melt faster and cut butter into dices. Prepare to melt in the pot. Next ,pour the chocolate and butter in the pot and stir well and set aside to cool around 5-7minutes trick to melt chocolate or butter is avoid chocolate or butter is heated directly because it burns how to make a bowl, then place in a pan of hot water and it will dissolve itself. Although it takes a lot and be careful not to splash down into the bowl of chocolate or butter. In addition, water used to melt chocolate it should be hot enough to melt the chocolate making should not use boiling water. Add sugar and stir well again then Stir until the sugar begins to melt , add eggs gradually add the eggs and stir again. Add vanilla extract ,flour and salt and stir well .