Portuguese Egg Tarts (葡式蛋挞)

Your egg tarts look more like curry puffs! That's what one reader says about Rasa Malaysia's Portuguese egg tarts.

Indeed, her tarts don't have any of the signature black burn marks. To me, what's supposed to be the custard looks more like an omelette . . . or maybe quiche filling.

Do you know what's wrong with Rasa Malaysia's recipe?

It's the shortcrust pastry she uses. Hong Kong egg tarts may be made with either shortcrust or puff pastry but their Portuguese cousins are always made with puff pastry. Why? Because, to get the hallmark splodges on the custard, the tarts have to be baked at a very high temperature. How high? About 250°C, which would have shortcrust pastry incinerated. That's why Rasa Malaysia bakes her tarts at 200°C. At that temperature, the shortcrust pastry doesn't burn but then neither does the custard even when it's overcooked (you can tell from the leathery, crumpled top).

If someone said to me that thing in her photo is a Portuguese egg tart, I would say, "On which planet?" Krypton maybe?

If you replace the shortcrust pastry in Rasa Malaysia's recipe with puff pastry and increase the oven temperature, would the egg tarts turn out ok?

Nope, because her custard filling doesn't have enough milk. You know how milk forms a skin when heated? The custard has to form the same skin and it's that skin that's burnt, not sugar or custard. What is that skin? It's a film of the milk proteins, whey and casein, which is formed when milk is heated. Too little milk means too little protein; too little protein means no skin; no skin means no burn marks even at 250°C, at least not before the pastry's burnt.

A lot of people think PETs' burnt splodges are bits of caramelized sugar. But sugar, or rather sucrose, turns black only when it hits at least 210°C. At that temperature, the pastry would turn black too. Milk proteins, OTOH, brown at a much lower temperature. That's why it's burnt when the pastry and sugar aren't.

Besides a layer of burnt protein, there's something else lurking atop the custard. You notice how shiny the custard is on top? The shine is because of melted sugar, not protein because protein isn't shiny. Some of the sugar separates from the custard mixture when it's heated at 250°C. It then bubbles up to the top, giving the tart its shiny look.

Separated sugar's a good thing except not all of it finds its way up if there's a lot. Some of it may sink to the bottom of the tart and turn the pastry soggy. How do you tackle this problem? By controlling the amount of sugar that separates from the custard mixture. How do you do that? By keeping the oven temperature low if you were baking Hong Kong egg tarts. For Portuguese egg tarts which must be baked at a high temperature, you do it with cornflour. The flour stabilizes the custard and, hence, reduces the amount of sugar separated.

To activate the binding quality of cornflour, it has to be added to the custard and then heated on the stove till the whole mixture reaches the right consistency. If it's too thick, it'll turn into scrambled eggs when it's baked. If it's too thin, it'll allow too much sugar to separate, turning the pastry soggy.

Unless you're making your own pastry, the only tricky step in making Portuguese egg tarts is when you cook the custard on the stove. Remember the thickening is a one-way street. If you overshoot, there's no turning back. Adding milk to thin it down doesn't work. Once the consistency looks right, you should put the pot in a water-bath to cool down quickly.

If you look at online photos of PETs, you'll see that a lot of store-bought tarts have a sunken top. Even Lord Stow's, the gold standard, are picture perfect only some of the time, i.e. when there's a press review!

How do you stop the custard from sinking as it cools down so that the top stays level?

Again by stabilizing it with cornflour. You see how important the cornflour is but it's missing from Rasa Malaysia's recipe?

And what's with her three drops of vanilla extract for 10 tarts? Three drops? Would these be three American plus-sized drops?

If you use readymade pastry shells, making Portuguese egg tarts is a cinch . . . . Well, it is provided you're not using a crap recipe like Rasa Malaysia's. Here's my video to show you how to make Portuguese egg tarts that look like Portuguese egg tarts rather than curry puffs or mini quiches:

MACAU STYLE PORTUGUESE EGG TARTS (葡式蛋挞) (Recipe for 9 tarts) 60 g dairy cream, 35% fat 60 g sugar 2 egg yolks, 30 g 1 tbsp cornflour 260 g full-fat fresh milk ½ tsp vanilla extract 9 frozen puff pastry shells, each measuring 7 x 3 cm (top D x H) To make custard filling, whisk cream, sugar, yolks, milk and cornflour till smooth. Stir over medium-low heat till thick enough to coat pot thinly (or metal spoon if using non-stick pot). Place pot in water-bath. Add vanilla extract. Stir till mixture is half-cool. Leave to cool completely. Preheat oven to 250°C. Line baking tray with aluminium foil, shiny side up. When oven is ready, remove pastry shells from freezer. Place slightly apart on baking tray. Fill shells with custard to 5 mm from edge. Bake till crust is brown, and custard is burnt and just stops bubbling. This takes about 30-35 minutes. You should check every 10 minutes and rotate tray as necessary so that all tarts brown evenly. Remove tarts from oven to wire rack. Leave till cool. Serve within a few hours whilst pastry is crisp. Leftovers should be unmoulded before pastry softens, then refrigerated uncovered (make sure there isn't any funky odour in your fridge). Reheat tarts on foil lined baking tray at 200°C. Pastry would turn soggy after 5 minutes, then crisp up nicely after another 5 minutes or so. Custard would be creamy and smooth but a bit sunken.