Hazelnut and Vanilla Slice

Last week Stephanie Meyer had a little get-together to celebrate Imen McDonnell being in town. Imen’s cookbook, Farmette, came out recently, and it is beautiful, filled with recipes and stories from her life on an Irish farm. Imen was just as lovely and kind in person as I imagined. I made the Wild Hazelnut and Vanilla Slice from her book – a perfect rectangle consisting of puff pastry, thick vanilla custard, and hazelnuts.

You can check out Imen’s blog here, and her book here. I highly recommend both.

Hazelnut and Vanilla Slice
Adapted from Farmette Cookbook, by Imen McDonnell.

The custard filling can be made the day ahead, to save time. I recommend baking the puff pastry the day the dessert will be served.

1 pound frozen puff pastry (2 sheets), thawed

Filling
1 1/2 cups (375 ml) whole milk
1 1/2 cups (375 ml) heavy cream
1/4 cup (60g) unsalted butter
2 teaspoons pure vanilla extract
2/3 cup (150g) granulated sugar
1/3 cup (40g) cornstarch
1/2 cup (125 ml) water
6 large egg yolks

Glaze
3 tablespoons whole milk
1 1/4 cups (156g) powdered sugar
1 cup (110g) chopped hazelnuts, for garnish (I lightly toasted mine)

For the Puff Pastry
Preheat the oven to 350F. Line two half sheet pans with parchment paper.

Lightly flour a work surface, and roll one sheet of the puff pastry into a 10 1/2-inch square, adding more flour as needed so the puff pastry doesn’t stick. Trim the sides of the square if needed so they are straight. Place the puff pastry on one of the prepared trays, then repeat with the other sheet of puff pastry. Top each tray of pastry with another baking tray as a weight and bake for 25-35 minutes, or until puffed and golden (the puff pastry won’t puff up like normal because of the baking tray on top, but you still will see some layers. Keep an eye on it so it doesn’t burn). Remove the trays from the oven and place them on a wire rack. Remove the top tray and let them cool completely.

For the Filling
Place the milk, cream, butter, vanilla, and sugar in a saucepan over medium-low heat; cook until hot but not boiling.

In a small bowl, mix the cornstarch and water to a smooth paste; whisk into the hot milk mixture.

Gradually add the egg yolks, stirring constantly while simmering for 6 minutes, or until the mixture has thickened. Remove from the heat. Transfer the mixture to a bowl, and place a piece of plastic wrap over the top of the custard, so a skin doesn’t form. Move the bowl to the refrigerator and let cool.

To Assemble
Reline one of the baking trays with parchment paper. Place one of the pastry sheets on the tray, and spread the custard filling over it. Top with the remaining pastry, and refrigerate for two hours, or until set.

For the Glaze
Mix together the milk and confectioner’s sugar in a small bowl. Drizzle the glaze over the pastry and sprinkle liberally with the hazelnuts. To serve, slice into rectangular pieces.