Paris-Brest with praline mousseline

Toast the almonds and hazelnuts on the stove or in a 350F / 180C oven about 10 minutes; rub in a kitchen towel so the steam peels the hazelnuts.

In a very hot skillet, cook half the sugar dry until brown, then add the other half (dry caramel; a wet caramel for a much larger batch).

Coat the nuts in the caramel, shape into a block and flatten; cool completely and break into pieces, saving some for garnish.

With the blade running, add the caramelized nuts and blend about five minutes, until it turns into a paste.

For the pate a choux, bring milk, water, sugar, salt and butter to a boil; remove from the heat and stir in the flour.

Return to medium-high heat, stirring constantly, until the mixture pulls away from the sides and a film forms on the bottom, about a minute.

Beat in the eggs, in a stand mixer or by hand after cooling a few minutes so the eggs do not cook into dots.

Pipe a half-inch (1.2 cm) thick ring just outside a 6-inch (15 cm) circle drawn on parchment, a second ring outside and touching it, and a third on top along the seam.

Dust with powdered sugar and coat with lots of sliced almonds; tip off the excess, holding the parchment.

Bake at 350F / 180C for 40 minutes without burning the almonds.

Variation: for individual cakes, pipe 3-inch (8 cm) rings with a narrow open star tip in the same way.

For the mousseline, bring milk to a simmer; beat egg yolks with sugar, then add the flour and starch.

Off the heat, whisk the hot milk gradually into the yolks; return to the stove and cook 2 minutes on medium-high, whisking constantly.

Off the heat, whisk in a third of the butter; spread on a plastic-wrap-lined baking tray, cover with plastic wrap in contact, cool to room temperature and chill.

Beat the chilled custard on high until smooth, mix in the hazelnut praline paste, add the remaining room-temperature butter and beat on high five minutes.

Split the baked shell horizontally, pipe the praline mousseline into the hollow twice with a medium open star tip, and add crushed caramelized nuts; fill the individual ones the same way.