In a pan, heat water. Add sugar and butter and let the mixture come to boil. Add orange rings very carefully to avoid breaking and cook for a minute. Remove the pan from the heat and let it cool down.
Grease a baking pan with oil and arrange these orange slices at the base. Pour little syrup as well and keep it aside.
In a bowl add the sugar and oil; mix it well. Add curd, orange zest and orange food colour.
In another bowl sift together flour and baking powder. Gradually add the flour mix to the above wet ingredients and mix all the ingredients. Add in the orange juice and mix again.
our this cake batter over the orange slices in the baking pan. Even out the layer using the back side of spoon. Tap the pan 2-3 times.
Bake the cake on low rack in preheated microwave at 170 degrees for 25 minutes. Once ready check until the tooth pick inserted in the center comes out clean.
Remove the cake from microwave and allow it to cool down. Once cooled, carefully turn the cake upside down on to a serving plate.