These egg tarts are apparently the best in Hong Kong. I haven't tried Tong Heng's famed egg tarts so I can't strike a comparison between the two, but being rather discerning when it comes to egg tarts, I personally find these to be decent, though a bit pricey.
Original Egg Tart, biscuit crust
I tried the Original ($1.60 each) with both a biscuit crust and a pastry crust which is apparently composed of 384 folds, as well as the egg white, durian and green tea ones ($1.80 each). My favourites are the original (I like both crusts) as well as the durian one, which was had delightfully pungent durian flesh sitting in the velvety, wobbly custard encased in the crumbly but sharp biscuit crust.
The egg white tart was a tad too milk-tasting for my liking, while the one that came with green tea-flavored custard didn't stand out.
Devour those with pastry crusts on the spot to savour the wonderfully flaky yet crisp texture of the crust. You'll be left craving for more! They also sell egg tarts with red bean and corn fillings.
On a side note, there was a stall in Clementi Central next to where McDonalds used to be called K-Pie which sold fabulous Portugeuse egg tarts. Oh boy, they were so good, they beat Madeleine's hands down. Now that CityVibe has taken over that plot of land, that stall has sadly disappeared. Does anyone know where it has relocated?