My mother’s berry custard tarts are legendary, and always perfect. Whenever I make a berry custard tart, however, there is at least a 20% chance that my custard will spitefully and wilfully refuse to set. Most recently this happened last summer, when my great-uncle asked me to prepare dinner for him and some special guests. For dessert I served them strawberries which sat like little islands among haphazard pieces of crust in a pool of completely liquid custard. It tasted nice, but it was definitely not a custard tart. (I still do not understand why I can make a perfectly lovely custard most of the time but get stage fright when I’m making a tart.) This year, I spent the Fourth of July with my family in upstate New York. I cleverly decided to make berry custard tarts so I could take advantage of that inexhaustible fount of culinary knowledge, my mother. The secret? My mother CHEATS.
Doesn’t that sound terrible? In fact, this is born of expediency. Specifically, my mother tries to cook with less egg yolks (cholesterol, etc.), so she thickens her custards with a smidgen of potato starch. I swear you can’t tell, except that the custard is just a tiny bit less rich than it would otherwise be. On the Fourth of July it was HOT in upstate New York, so a light custard sounded more appealing than a rich eggy custard. If, however, you are a custard purist, you should substitute three to four additional egg yolks for the potato starch.
The crust of these tarts has a lovely nuttiness from the addition of ground almonds, but feel free to try other nuts, like ground hazelnuts (with blackberries!) or pine nuts, or even macadamia nuts. Since the raspberries and blueberries I used were so fresh and beautiful, I did not glaze these tarts. For strawberry tarts, you can (if you wish) make a glaze by simmering some strawberries in sugar until the juice from the strawberries is thick, and painting this on your berries when your tarts have been assembled and cooled, or you can glaze with a simple sugar syrup.
Also, I feel compelled to point out: While these tarts undeniably are thematically suitable for the Fourth of July (as per usual, I’m late with my holiday postings) the tart decorated by my eight-year-old niece is a lot more Union Jack than Stars and Stripes, and she HASN’T EVEN BEEN LIVING IN LONDON FOR THE PAST THREE YEARS.
For the crust:
1 and ¼ cups white flour (about 125-150 grams)
1 cup ground almonds or almond flour (about 150 grams)
¼ cup granulated or caster sugar (about 50 grams)
½ pound (about 400 grams) cold unsalted butter, cut into chunks
½ teaspoon salt
For the custard
1 and ½ cups milk
½ cup cream
¼ cup sugar (about 50 grams)
3 egg yolks
1 and ½ teaspoons potato starch
½ vanilla pod or 1 teaspoon vanilla extract
** You will also need two spring-form pans and at least a quart of fresh seasonal berries of your choosing. Err on the side of too many berries, as you will be cranky if you run out.
For the crust:
Thoroughly combine your dry ingredients in a food processor or large bowl. Add the butter and pulse until the mixture resembles coarse crumbs. (You can also do this with two forks.) Slowly add just a little ice water. If you’re using a food processor, dribble in the water while the processor is mixing until the mixture starts to adhere into a ball. You should not require more than a few tablespoons. Wrap the dough well in plastic and chill for a minimum of two hours.
After the dough has been chilled, preheat the oven to 420 degrees Fahrenheit (about 210 degrees Celsius). Divide the dough in two pieces (you are making two tarts) and roll out, using plenty of flour to prevent sticking, on wax paper, until you have a roughly round sheet of dough a couple of inches larger in diameter than your spring-form pans. Aim for a thickness of about ¼ inch. (I like to roll out dough between two sheets of wax paper or even plastic wrap.) Carefully invert the wax paper and transfer the pastry to your pans. Chill in your freezer for about 15 minutes to allow the dough to set.
Prick the bottoms of your crusts with a fork several times and weigh down the bottoms with pie weights. (You can also use about a cup of dry beans spread over parchment paper.) Bake for about 15 minutes in the center of your oven, then remove the weights and continue to bake for another 15 minutes or so or until crusts are crisp and golden brown. Cool on a wire rack.
For the custard:
While your crust is chilling, combine the milk and cream in a double boiler or heavy saucepan, reserving a couple of tablespoons. (If using a vanilla bean, add the pod to the milk-cream mixture and slowly steep over very low heat (so the milk does not boil) for about 10-15 minutes, then remove the pod.) Stir the potato starch into the reserved milk in a small bowl until completely smooth, then add to your milk mixture, along with the sugar. Heat the mixture over low heat until very hot but not boiling.
Whisk together the egg yolks. Slowly add about 1/3 cup of the milk mixture to the egg yolks, whisking all the while, to temper them. Then very slowly add this to the milk-cream on your stove, whisking vigorously, until thoroughly combined. (If using vanilla extract, you can add it at this point.) Continue to cook over low heat, whisking, until your custard is thickened. The custard is thick enough when your whisk leaves faint marks on the surface, or when if you spoon some out it stays on the spoon without dribbling out like a liquid would. Remove from heat and give a few more swipes with the whisk for good measure.
Strain through a wire mesh strainer into a stainless steel bowl and cover with plastic wrap so the wrap touches the surface of the custard (this prevents a skin from forming). Chill until completely cold, about three to four hours.
Smear the custard in your pre-baked tart shells to a thickness of about ¾ inch. Decorate the surface liberally with fresh berries. Chill the tarts for at least 30 minutes before serving to set.
Makes two eight- or nine-inch berry tarts.