This pie is an old-fashioned looker, made by hand. You can consider it a rustic variation on pecan pie, a brawny northern cousin that's caramelly sweet but unexpectedly subtle. A bit flannely, with a generous smile. That sort.
You'll see there's two brown sugars in the filling. I thought all dark might be too heavy, and all golden might be too anemic - but using only one or the other would be perfectly fine in a pinch. The one thing can't be fiddled is the maple syrup, which needs to be proper stuff.
Choose the grade you're fond of, or if you come across some smokily intense maple syrup, then that's the one to invite along. It'll hang around with the toasty-edged walnuts and get on like best mates.
Their companionship is both complimented and tamed by the boosted creaminess brought by a swirl of evaporated milk (I know!) stirred in with the eggs. And the oats! Those oats, they're tricky misters; what a difference a soak and a bake make. The oats fluff up, lose their form and give the pie a pleasant density, setting the custard soft and pudding-like, underneath the cobblestone crust of walnuts that float to the top and go crunchy.
The recipe is adapted from The Egg Farmers of Ontario.
Makes one 8-inch pie, serving 8-10
1/2 cup chopped walnuts
1/2 cup golden brown sugar, packed
1/2 cup dark brown sugar, packed
1/2 cup old fashioned oats
1/2 cup evaporated milk
1/2 cup maple syrup
1/4 cup butter, melted
Seeds scraped from half a vanilla bean or 1 teaspoon vanilla extract
1/4 teaspoon kosher salt or 1/8 teaspoon table
1 unbaked 8-by-2-inch chilled pastry shell, see note
Granulated sugar for sprinkling
One egg white for brushing plus 3 whole eggs, lightly beaten
Preheat an oven to 400°F (205°C).
In a dry skillet over medium heat, toast the walnuts until golden and fragrant. Remove to a bowl and set aside.
In a large bowl, whisk together sugars, oats, evaporated milk, maple syrup, melted butter, vanilla and salt.
Prick the pastry all over with a fork. Cover with foil and bake for 15 minutes, pressing down any puffed areas with the back of a spoon gently if necessary. Remove the foil and bake for 10 minutes more, the crust should be starting to look dry in places. Remove the crust from the oven, brush all over with a thin coating of the egg white, and sprinkle edge with granulated sugar, if desired. Return to the oven to bake for 1 minute more.
Set aside the crust to keep warm, and reduce the oven temperature to 350°F (175°C).
Stir the toasted walnuts into the filling, along with the whole eggs. As soon as the oven reaches temperature, pour the filling into the still-warm crust and bake until puffed at the centre and set with little wobble, about 60 minutes. Transfer to a baking rack and cool completely before slicing.
I changed the size of the pie, as the greater ratio of filling to pastry made for a more satisfying bite. A pâte brisée recipe for a 9 or 10-inch pie will allow for the extra depth of a 8-by-2-inch pie plate. If using a store-bought pie shell, which are usually 9-inch, reduce the cooking time to around 40 minutes.