Though buttermilk pie (a plain version here) is generally credited as a Southern pie, it is also prevalent in Yankee traditional cooking and baking. That's mainly because on dairy farms and in farming communities, buttermilk was cheap and readily available, the liquid left behind when butter is made. Today though, most commercial buttermilk is not real. It's made from low-fat or skim-milk that's mixed with bacterial cultures to make it sour, and other additives to make it thick. As you might guess, this artificially-produced buttermilk doesn't taste as good as the real deal. According to Julia Moskin of The New York Times, "Many home cooks keep buttermilk on hand for pancakes, ranch dressing or corn bread. They might know that it makes more tender cakes (because it softens the gluten in flour), loftier biscuits (its acid boosts leaveners like baking soda and baking powder) and thicker dressings (lactic acid in buttermilk gently curdles proteins into a smooth mass)." Now you see why you might want to use the real stuff in a pie?
Classic buttermilk pie is essentially a custard pie (or custy pie), with an extra tang. It's also related to Chess pie--some Chess pie even calls for buttermilk. For this version, adapted from 101 Cookbooks, throw in a dash of bourbon, the barrel-aged whiskey from Kentucky, and maple syrup, the prized natural of many New England states (when I lived in Vermont I learned to put it in everything), and you've got yourself something fit for a table on either side of the Mason-Dixon line.
Maple Bourbon Buttermilk Pie
Adapted from 101 Cookbooks
Nothing-in-the-House pie crust, halved (I used 1/2 white whole wheat flour and 1/2 all-purpose)
Zest of 1 lemon
2 Tblsp. brown sugar
6 egg yolks
1/4 c. flour
2/3 c. maple syrup (preferably Grade B)
2 c. real buttermilk
1 tsp. vanilla extract
1 Tblsp. bourbon (I used Maker's Mark)
scant 1/2 tsp. fine grain sea salt
Large grain sugar or pink salt for sprinkling (optional)
1. Prepare half of the Nothing-in-the-House pie crust as per the directions. Chill dough at least 1 hour before rolling out and fitting into a greased and floured 9-inch pie pan. Place the pan in the fridge while you prepare the filling.
2. Preheat the oven to 375 degrees F. In a medium bowl, whisk together lemon zest, brown sugar, egg yolks, and flour until no lumps remain. Pour in the maple syrup and stir to combine. Then add buttermilk, vanilla, and sea salt, stirring until incorporated.
3. Pour filling into the pie crust and bake about 1 hour, or until filling is set and not wobbly. Remove from oven and let cool, then sprinkle with sugar or salt (I chose salt, surprise surprise). Serve slightly chilled or at room temperature with apple syrup (recipe below). Store in the fridge.
From my friend Marina of Shoving Leopard Farm
Makes 1 c. apple syrup
7 c. apple cider
1. Marina makes her apple syrup in the shallow maple syrup pans they have on her farm, but you can make yours in a Dutch oven or large stock pot. Pour your cider into the pot and bring to just a boil (cider boils at about 219 degrees F).
2. Once boiling, reduce heat to medium-low and let simmer until cider has reduced to about 1 cup, and reached a syrup-like consistence, thickly coating the back of the spoon. You can do this with more or less cider, but in general 7 parts cider yields 1 part syrup.