Well, as far as this being Harry Potter's favorite treacle tart of all treacle tarts, that might be an overstatement. After all, it's difficult--if not downright impossible--to match the mastery of the Hogwarts house-elves or the magical air of the Great Hall. Fans will know, however, that treacle tart is a favorite dessert of Harry's. Unfortunately, few in the US know the deliciousness of this British treat. Luckily, it's not difficult to make.
Step 1: Tart Pastry
2 cups all-purpose flour
1/4 cup granulated white sugar
1 tsp. salt
1 cup cold butter, cut into small pieces (leave in refrigerator until needed)
2 egg yolks
1/4 - 1/2 cup heavy whipping cream
1 tsp. vanilla extract
2 Tbsp. lemon juice
Whisk together the egg yolks, 1/4 cup heavy whipping cream, vanilla extract and lemon juice in a small mixing bowl. In a medium mixing bowl, add together the flour, sugar and salt. Put both bowls in refrigerator for about 30 minutes.
Put the dry ingredients in the food processor and pulse to combine (or if a food processor is not an option, mix it by hand). Add the butter and pulse (or cut in with a pastry blender) until texture resembles course crumbs. Put the mixture back into the medium mixing bowl and pour the small mixing bowl with the liquid ingredients over it. Stir just until combined. If dough doesn't pinch together add up to another 1/4 cup of heavy whipping cream a tablespoon at a time until it does pinch together.
Turn the dough out onto your clean work surface and divide in two. Shape each half into a flattened disc and plastic wrap it. Refrigerate for at least 2 hours (use with in 3 days).
Place one disc onto a well-floured work surface (tart dough is very sticky). Flour the top of the disc generously and the rolling pin. Roll the dough out so you have a 12" diameter. Roll from the center out, and rotate the dough occasionally to avoid sticking. Use a pastry brush to dust off the excess flour, and gently fold the dough in half. Dust the side facing up as well and gently fold in half again. Dust the showing quarter, turn over and likewise dust. Transfer the dough to a 9" tart pan and unfold. Gently push the pastry dough into the corners without stretching. Any tearing that occurs, use your fingers to patch back together. Roll the rolling pin over the pan edges to remove the excess dough. Refrigerate for about 30 minutes.
Roll the second disc out similarly. Cut 1/2" strips (pizza cutter works nicely) and place on a parchment lined cookie sheet. Refrigerate for about 30 minutes.
Step 2: Treacle Filling
1 cup golden syrup
(1 Tbsp. black treacle)*
2 cups of fresh bread crumbs (about 3-4 pieces of bread cut up and then put in the food processor)
Zest of 1 lemon
Juice of 1/2 lemon
Pinch of ginger
* Note on the black treacle: I omitted this, as it is difficult to find in the US, but the tart is tasty even without it.
Preheat the oven to 375 degrees F.
Pour the golden syrup in a small mixing bowl and add the black treacle. Place the bowl in a larger mixing bowl with shallow hot tap water for about 10 minutes. Add the bread crumbs, lemon rind, lemon juice and ginger, and mix by hand with the small bowl remaining in the hot water bath.
Step 3: Assembly & Baking
1 egg, separated
1 Tbsp. heavy whipping cream
Brush the tart dough in the pan with egg white. Pour and spread even the treacle filling over it. Layer the strips of pastry dough across the top about 1/2" apart in parallel, trimming the edges as you go. Do a second layer similarly, either perpendicular to the first layer or at another angle to create a diamond effect. Whisk together the yolk and cream, and brush the top crust. Bake for 20-25 minutes, until top crust is golden brown. If using a tart pan with a removable bottom, bake on top of a parchment-lined cookie sheet.
Serve warm with vanilla ice cream or whipped cream. Garnish with berries for some color.
Enjoy your little slice of magic!