Whisk together flour, cinnamon, nutmeg, sugar, and salt in a large bowl.
Pinch cold butter chunks into flour mixture until pea-sized pieces form.
Add ice water 1-2 tablespoons at a time until shaggy dough forms.
Form dough into a ball, wrap in plastic, and refrigerate for 1 hour.
Preheat oven to 425F and roast sweet potatoes on a parchment-lined baking sheet for 35-45 minutes until fork tender.
Brown butter in a skillet over medium heat for 3-5 minutes until golden and nutty, then set aside to cool.
Remove skins from cooled sweet potatoes and mash flesh until smooth, removing any stringy fibers.
Mix mashed sweet potatoes with cooled brown butter, brown sugar, white sugar, cinnamon, ginger, nutmeg, cloves, and evaporated milk.
Add vanilla extract, flour, and eggs, mixing until smooth.
Roll chilled dough into a 10-inch circle and place in pie pan, trimming excess and crimping edges.
Freeze shaped crust for 20 minutes.
Poke holes in bottom with fork, line with parchment paper, and add pie weights.
Bake at 425F for 17-20 minutes until edges are golden.
Remove weights and parchment, then bake another 12-13 minutes until bottom is golden.
Pour sweet potato filling into par-baked crust.
Reduce oven to 350F and bake for 35-40 minutes until center has a slight jiggle.
Cool completely on wire rack for 2-3 hours before serving.
For meringue, whip egg whites on high speed with cream of tartar for 1 minute.
Slowly add brown sugar while mixing until glossy peaks form, then add vanilla extract.
Pipe or spoon meringue onto cooled pie and torch to brown if desired.