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How to make bostock, a nutty French pastry, using leftover cake or bread

(Laura Chase de Formigny for The Washington Post/food styling by Lisa Cherkasky for The Washington Post)
Panettone Bostock
Active time:20 mins
Total time:50 mins
Servings:6 to 8
Active time:20 mins
Total time:50 mins
Servings:6 to 8

Among the lesser-known offerings in the average French pastry case, near the piles of croissants, stacks of brioche and rows of eclairs, is the bostock.

Traditionally, it’s a square slice of stale brioche, brushed with a sweet syrup and covered in a thick layer of frangipane or almond cream. A sprinkle of sliced almonds or bits of fruit may garnish the top before it’s baked. It emerges golden and crisp around the edges, but still pillowy soft in the center. Sweet and dense, it’s lovely dipped into a warm cafe au lait, or with a cup of hot tea.

Similar in flavor to an almond croissant, bostock was likely invented as a way to use up leftover sweet breads. The process is easy to replicate using almost any tender bread or cake — including slices of white bread, milk bread, challah or pound cake — so here, it’s applied to panettone.

A great panettone, airy and golden, needs no accompaniment — and will probably be eaten within hours. This recipe is for the lackluster loaves with dense or dry interiors.

Start by making a not-too-sweet syrup, which you’ll use to moisten the slices of panettone. It can be flavored with almost anything. Orange blossom water is a common addition, as it complements the flavor of almonds, but rose water, vanilla, a strip of citrus zest or splash of liquor work just as well.

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Next, make the frangipane. Any nut works just fine in this recipe, including almonds, which are classic. Pecan and walnut frangipane is especially rich; pistachios produce a faintly green frangipane.

Spread the frangipane onto the moistened slices of panettone and bake them as-is, or dress them up with pieces of fruit or a sprinkle of nuts.

This cranberry custard trifle uses leftover panettone instead of cake

For the prettiest presentation, cut a loaf of panettone across its equator to get large, round slices.

This recipe is great for using up almost any leftover enriched bread or cake, so as long as the slices are about 1-inch thick, it doesn’t matter what shape they are. So, if your slices are smaller than what’s called for here, don’t fret. Moisten as directed, spread with a 1/3-inch-thick layer of frangipane and bake, keeping in mind that baking time may be shorter for smaller slices.

For best results, avoid panettone that contains a lot of chocolate, as it can burn during baking.

If your loaf is still quite moist, dry slices out in a 300-degree oven for 10 to 20 minutes.

Make Ahead: The syrup and frangipane can be made up to 2 days in advance.

Storage Notes: Extra syrup and frangipane can be refrigerated for up to 2 days. Leftover syrup may be strained and used to sweeten tea or other beverages.

Where to Buy: Panettone is available online or at well-stocked grocery stores around the holidays.

NOTE: Almonds, pistachios, pecans, pine nuts, hazelnuts, cashews and macadamia nuts will all work. Nuts may be roasted or raw.

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Ingredients

For the syrup

  • 1/4 cup (60 milliliters) water
  • 2 tablespoons granulated sugar
  • 1/2 teaspoon orange blossom water or rose water (optional)

For the frangipane

  • 1 cup (100 to 120 grams) shelled, unsalted nuts, such as pistachios or almonds, preferably blanched (see NOTE)
  • 1/4 cup (50 grams) granulated sugar
  • 1 large egg
  • 2 tablespoons unsalted butter, melted
  • 1/4 teaspoon fine sea or table salt
  • Two (8-inch wide, 1-inch thick) slices panettone, cut across the equator, stale or dried out (see headnote)
  • Slices of fresh, dried or poached fruit or chopped nuts (optional)
  • Confectioners’ sugar, for serving (optional)

Step 1

Make the syrup: In a small saucepan over high heat, combine the water and sugar. Stir until the sugar dissolves, about 1 minute. Remove from the heat and stir in the orange blossom water or rose water, if using. Set aside to cool.


Step 2

Position a rack in the middle of the oven and preheat to 350 degrees. Line a large, rimmed baking sheet with a silicone mat or parchment paper.

Make the frangipane: In a food processor, process the nuts and sugar until the nuts are finely ground, stopping to scrape down the sides of the bowl if necessary. Add the egg, butter and salt and process until smooth.


Step 3

To assemble: Place the stale or lightly toasted panettone slices on the prepared baking sheet. Using a pastry brush or spoon, brush the panettone with the syrup until it is soft and moist but not completely soaked. You may have leftover syrup; reserve for another use.


Step 4

Using a tablespoon or offset spatula, spread about 1/2 cup of frangipane in an even, 1/3-inch-thick layer over each soaked slice of panettone. Depending on the size of the slices, you may have some left over. Top with fruit or chopped nuts, if desired.


Step 5

Bake for 30 to 35 minutes, or until the frangipane is set and lightly browned along the edges. Serve warm or at room temperature, sprinkled with confectioners’ sugar, if desired.


Nutrition Information

Per serving (1/4 slice) based on 8, using half the syrup

Calories: 299; Total Fat: 15 g; Saturated Fat: 6 g; Cholesterol: 65 mg; Sodium: 191 mg; Carbohydrates: 34 g; Dietary Fiber: 2 g; Sugar: 24 g; Protein: 7 g

This analysis is an estimate based on available ingredients and this preparation. It should not substitute for a dietitian’s or nutritionist’s advice.


From staff writer G. Daniela Galarza.

Tested by Becky Krystal; email questions to voraciously@washpost.com.

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