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Squares of brioche topped with sliced almonds and powdered sugar lined up on a red bakery tray.
Steel & Rye’s almond bostock.

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This Pastry Made From Bread Scraps Is the Best $5 You’ll Spend This Month

Steel & Rye head baker Aditya Sastri’s almond bostock is worth seeking out in Milton

Crunchy, sweet, and light, a traditional French bostock is comprised of day-old brioche, frangipane (almond cream), almonds, and a dusting of powdered sugar. It first appeared in France during the 1930s and takes some of the same cues as French toast, as both are sweet treats that use leftover bread. In the U.S., the bostock generally gets less airtime compared to its spotlight-hugging French siblings like the chocolate croissant, but at Milton restaurant and bakery Steel & Rye, the pastry shines on the menu.

Head baker Aditya Sastri’s bostock retains many elements of the traditional French pastry, including brioche, frangipane, almonds, and powdered sugar. But Sastri’s creation also uses leftover croissant dough trimmings that are usually thrown away, along with a more generous helping of frangipane. “It’s the best part of an almond bostock,” says Sastri.

Two hands in black surgical gloves are visible holding bread and spreading pastry cream over top.
Slices of brioche are spread with a generous dollop of frangipane.
A corner of a baking sheet is visible with four bostocks laid out on top. A hand dusts powdered sugar from a strainer over top of the pastries.
The bostocks are finished with a dusting of powdered sugar.

Perfecting this versatile croissant dough took over three months and required extensive experimentation, like braiding the dough so the trimming didn’t fall apart coming out of the oven. To make the bostock, Sastri used day-old almond croissant dough that he dipped in simple syrup and slathered with frangipane. It was a waste of ingredients to specifically create a product that uses leftover dough (the almond croissant), so the bostock temporarily became a sustainable replacement for Steel & Rye’s almond croissant, until Sastri was able to find a waste-free way to keep both pastries on the menu. Customers were confused at first by the change, he says, but quickly became fans of this French pastry. It soon became a permanent addition to the menu.

“I wanted to give people something delicious, unique, and not easily obtainable,” Sastri says. “The bostock fits that perfectly.”

A man in a tan chefs apron stands in a production kitchen with a baking tray filled with square almond bostocks.
Steel & Rye’s head baker Aditya Sastri with a pan of almond bostocks.

Originally from Bengaluru in southern India, Sastri wanted to be a chocolatier before he discovered his love of bread. His career had taken him across the U.S., from California to Texas, including a stint at the Culinary Institute of America where he was a student and then the head bread baker at the storied culinary school. He moved to Boston in 2016 and started laying down roots, baking his way around town at places like Tatte and Brookline’s gone-but-not forgotten cafe Allium Market. Sastri met Steel & Rye’s owner, Dan Kerrigan, in 2021.

Kerrigan gave Sastri free rein to expand and reshape Steel & Rye’s pastry program, which first started as an offshoot of the restaurant in 2020. A cafe and bakery had been something Kerrigan wanted to do for a while; he made it happen by converting Steel & Rye’s popular private dining room into the bakery kitchen. Once Sastri came on board, one of his top priorities has been to reduce waste in food production, he says. He embodies this philosophy in not just the bostock but also other items on Steel & Rye’s pastry menu, including a seasonal strawberry danish that utilizes every part of the fruit. Bostocks aren’t the only items the croissant dough is used for — it also shows up in croutons, French toasts, and bear claws at the Milton bakery.

Steel & Rye is located at 95 Eliot Street in Milton. The bakery is open from 7 a.m. to 4 p.m. on weekdays and 8 a.m. to 4 p.m. on weekends. Closed on Mondays.

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