I think we can safely count the claim made by the proprietors of the Antiga Confeitaria de Belém bakery — that they bake pastéis de Belém at 750 degrees Fahrenheit — as a myth (of the intentionally created variety). Probably a diversionary tactic they use to discourage people from trying to make their pastéis at home.
I confess I had my doubts going into this. Elementary baking science dictates that extremely high heat is useless for everything from small tarts to Thanksgiving turkeys. Indeed, the larger and more massive the thing that goes into an oven, the lower the heat needs to be to cook it all the way through. The smaller the item, the higher the heat can be without risk of burning the exterior. Thus a 2-pound cornish hen can be roasted at 425 for 50 minutes, but a 15-pound turkey needs more like 350 and several hours. By that logic the only tart you could bake safely at 750 would be one the size of a dime, and you’d leave it in for 17 seconds.
Thursdays (unless I have pressing projects going) are bread baking days. I fire up the brick oven in the back yard and bake off ten or so loaves. Once the oven is fired and scooped out, it needs about 45 minutes to cool down from 700-something (its usual post-fire temperature) to around 600, the point at which I start loading. It’s the perfect window for a pastéis de Belém experiment.
Wanting to be conservative, I shaped four, poured in the custard mix, and slid the pan into the bricks. Then I set about getting my various accoutrements ready for the bread bake. Sure enough, not five minutes later I detected a whiff of burning pastry. I checked and saw bubbling filling and charring edges. I got out the laser thermometer and did a temperature check: 714 degrees. I decided to press on since the filling was still liquid. Five minutes later and the pastries, to put it in Scotty’s vernacular, could tak noo moore! Here’s how the tops looked:
Here’s what the bottoms were like.
And as for the interior, as expected, runny and raw.
I think we can declare this myth officially busted, as they like to say on the show. But I’m glad I tried, even if it was a sinful waste of good home made pastry.