Praliné religieuse

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

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

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

With the blade running, add the caramelized nuts and blend about 5 minutes until a paste.

Beat the custard on high until smooth, mix in the praliné paste, add the remaining room-temperature butter and beat on high 5 minutes.

Slice the tops off the choux and trim with a round fluted cutter.

Fill the bases generously with praliné filling, set the lid upside down and fill with whipped cream; fill the heads with praliné filling, crushed caramelized nuts and more whipped cream, and put the hat back on.