Preheat oven to
180º C. Grease an ovenproof glass dish.
Sieve together refined
flour, cocoa powder and baking powder into a mixing bowl.
Take butter and sugar
in another bowl and beat with an electric beater till light and fluffy.
Add the flour mixture,
a little at a time, and continue to beat till well mixed.
Add milk, a little at a
time, and mix well.
Transfer the batter into
the glass dish, keep the dish in the preheated oven and bake for 10-15 minutes.
Bring the glass dish out
of the oven and demould the cake onto a platter. Poke a few holes in the cake with a skewer. Pour the chocolate sauce over it and spread it evenly with a butter knife.
Sprinkle the gems all
over the surface. Cut into squares and pack into tiffin boxes.