Grease a deep baking dish. Cover the base with the pears.
Sift the flour, salt and baking powder into a bowl. Put the butter, vanilla essence and chocolate into a saucepan, stir until melted and then remove from the heat.
Beat in the sugar, eggs and pecans. Stir the chocolate mixture into the dry ingredients, pour the batter over the pears and bake in the centre of the oven for about 35 minutes or until the brownie mix is just firm.