Preheat oven to 180 Degree C.
Take flour, salt, baking powder, baking soda in a bowl. Mix well and set aside.
Take butter, sugar in a bowl and beat till creamy and fluffy.
Add in egg and vanilla, beat again and till fluffy.
Now add in flour mix and milk alternating, ending with flour.
Pour this into a prepared pan. Bake it for 25 to 35 mins.
Remove it and let it cool completely. once it is cooled, slice the dome off and cut into squares.
Now make jelly, make it as per package directions.
Now chill the jelly till it is ¼ way set.
Now take the cake and dip in the jelly mix, Roll in coconut and set aside.
For making coloured coconut, add few drops of food colour to the coconut and coat the cake in that.
Now chill the cake for 1 to 2 hours before serving.