Five layer birthday pie

Happy birthday to me! This year, I decided to celebrate by bringing wonderful friends up to Mono Hot Springs in the Sierras. The cabins there have kitchens, but I didn't particularly want to trust their ovens with anything more complicated than biscuits. So I spent rather a long time trying to come up with a good dessert that combines the virtues of transportability, novelty, and of course deliciousness.

This pie, with its sturdy and sweet layers of ganache, golden syrup, and oats, was the first to catch my attention. I'd also just noticed that Lester's rhubarb has been perking up for spring (no thanks to me whatsoever), which reminded me of the rhubarb and chocolate donuts that we had at Walrus and the Carpenter with Sarah ages ago. So to balance out the sweetness of the golden syrup, I added a layer of macerated rhubarb in between the chocolate and the oats, and a layer of mascarpone whipped cream on top.

It all came together beautifully, with a homey mixture of textures and flavors that goes splendidly with coffee, mountains, and old friends. Only caveat is that the crust was a bit tough after sitting in the fridge, so I'd try a more tender shortcrust next time.

crust (layer 0):
1.5 c flour
1/2 c powdered sugar
1 stick + 1 T cold butter, cut into small pieces
1 egg yolk (white reserved for layer 3)

Pulse together flour and sugar in the food processor. Add the butter and pulse to cut in. Add the egg yolk and pulse until it forms a dough. Press into the bottom and sides of a 9" springform pan, line with buttered foil, and freeze for 30-45 min. Bake at 375F for 30 min. Remove the foil and let cool while you make layer 1.

ganache (layer 1):
1/4 c cream
4 oz chopped dark chocolate (10 squares TJs pound plus)

Bring cream to a simmer over medium heat. Turn off the heat and stir in the chocolate until smooth. Spread evenly on the base of the pie crust. Place in the freezer to set while you make layers 2 and 3.

fruit (layer 2):
3 stalks rhubarb, sliced 1/4"
2 T sugar

Toss the rhubarb with the sugar, and set aside to macerate while you make layer 3.

flapjack (layer 3):
3/4 c brown sugar
5 T butter, melted
1/2 t cardamom
1/2 t salt
1 c golden syrup
1 T whiskey
2 t vinegar (white or cider)
3 eggs + 1 egg white (reserved from crust)

1.5 c oats

Whisk together the brown sugar and melted butter until smooth. Add each ingredient in turn, whisking until smooth after each addition.

assembly:

Spoon the rhubarb over the ganache to form an even layer 1-2 rhubarb slices deep, and discard any remaining liquid. Pour the oat mix over the rhubarb. Bake at 325F for 60-70 min until set around the edges and just barely set in the middle.

cream (layer 4):

4 oz mascarpone

1 c whipping cream

splash coffee bitters

Beat the mascarpone to soften, if needed. Add the cream and beat until it holds peaks. Beat in the bitters. Spread in an even layer over the cooled pie and chill until serving, or dollop on slices and serve immediately.