Adjust oven rack to middle position and heat oven to 350 degrees (Gas Mark 4).Grease by adding all of the 200g butter too the loaf pan,melt it in the hot oven and then when you have added the hot melted butter too the food processor - then sprinkle self-raising flour over the greased 9 by 5 - inch (or just under) loaf pan.Process sugar,eggs,vanilla,baking powder,and salt in food processor until combined,about 10 seconds,scraping down sides of bowl as needed.With processor running,slowly add hot

Melted butter until incorporated, about 10 seconds.Add flour and pulse until just incorporated,about 5 pulses; do not overmix.

(2) Transfer batter to prepared pan and smooth top.Gently tap pan on counter to release air bubbles.Bake cake until skewer inserted in center comes out with few moist crumbs attached,50 to 60 minutes,rotating pan halfway through baking.

(3) Let cake cool in pan on wire rack for 15 minutes.Remove cake from pan and let cool completely on rack,about 2 hours,serve.