Remove the pie dough from the fridge and on a lightly floured work surface, roll out dough to about ¼ inch thick and about 2 inches wider than your pie pan. Roll the pie crust into the pie pan and be sure to poke the bottom a few times with a fork to allow air to escape during baking. Cut away any undesired excess crust and crimp, curl, or decorate the edges however you like!
Chill the pie crust in the freezer for at least 30 minutes before baking (if you skip this step, the pie crust will shrink). While the crust is chilling, preheat the oven to 425°F.
Place a piece of parchment paper or heavy duty aluminum foil inside the pie crust and fill with pie weights (uncooked rice or dry beans also work great).
Bake at 425°F for 15 minutes. Carefully lift the parchment paper and pie weights then return the pie crust to the oven to bake for another 5 minutes or until the bottom just starts to brown.
Set aside and let cool while you make the filling.
Purple Sweet Potato Filling
Preheat oven to 400˚F. Prick the purple sweet potatoes a few times with a fork and wrap in aluminum foil. Place on baking sheet and bake for 1 hour until cooked through and soft.
Once cooked, scoop the flesh into a blender and blend until super smooth and creamy. You should have about 2 cups of mashed purple sweet potato.
To a large bowl, add 2 cups of mashed sweet potato, brown sugar, eggs, evaporated milk, melted butter, vanilla, pumpkin pie spice, and salt. Mix until fully combined and smooth.
Pour the purple sweet potato filling into the par baked pie crust.
Bake at 400˚F for 15 minutes, then reduce the oven temperature to 350˚F and continue to bake for 25-35 minutes until the edges are set and the center of the pie jiggles slightly.
Remove from oven and let cool to room temperature (about 1 hour). Then chill for at least 2 hours or until ready to serve.
Swiss Meringue
Create a double boiler by bringing 1-2 inches of water to a simmer in a small saucepan.
In the bowl of a stand mixer (make sure your bowl is heat safe - stainless steel is best), whisk the sugar and cream of tartar into the egg whites then set the bowl over your double boiler. Do not let the bottom of the egg whites bowl touch the water.
Whisk the whites and sugar constantly until sugar is fully dissolved and mixture has thinned out (about 3-4 minutes). If using an instant thermometer, it should read 160°F.
Place the bowl on the stand mixer and fit with the whisk attachment. On high speed, beat on until stiff peaks form and the meringue is no longer warm to the touch, at least 10-15 minutes. If it’s still not reaching stiff peaks, stop the mixer, place the bowl in the fridge for 10 minutes, then return to the mixer and continue beating until stiff peaks form.
Spread the meringue on top of the chilled sweet potato pie and use a culinary torch to toast the top of the meringue.
Notes
The purple sweet potato pie will last in the fridge for up to 3 days, but once topped with the meringue it’s best eaten immediately.Note: Most standard pie pans are about 1 inch deep. So if you're using a deep dish pie pan (1 ½ to 2 inches deep) this recipe will not yield enough filling to completely fill your pan and you may want to double it.