Get this pie prepped the day before, then bake the day-of.
Using a needle or a paring knife, pierce each cranberry in one or two spots. (This will help infuse the cranberries with lime flavor and prevent them from popping.) In a small saucepan, bring 1/2 cup sugar, the lime juice, and 1/2 cup water to a boil, stirring to dissolve the sugar. Add the cranberries and bring to a boil. Remove from heat and let stand until cool, about 1 hour. Transfer to a jar. Cover and refrigerate overnight.
Drain the cranberries well. (Reserve the syrup to make flavored sodas or cocktails.) In a small bowl, toss the cranberries and the remaining 1/2 cup sugar. Spread out on a baking sheet and let stand until dry, at least 4 hours.
For the crust, in a food processor, pulse the flour, salt, and sugar. Add the butter; pulse until chickpea-size pieces form, about 6 times. Add 4 tbsp. buttermilk; pulse until moist clumps form. Add the remaining 1 tbsp. buttermilk if the dough is too dry. Transfer the dough to a work surface. Knead a few times to bring the dough together. Form the dough into a ball; flatten into a disk. Wrap in plastic; refrigerate for 1 hour.
On a lightly floured work surface, roll out the dough into a 13-inch round. Transfer to a 9-inch pie dish, fitting the dough into the edges. Crimp the edges decoratively. Refrigerate for 30 minutes.
For the filling, preheat the oven to 350°. In a large bowl, whisk the sugar and flour. Whisk in the remaining ingredients. Pour into the crust. Bake the pie until the edges are set and the center jiggles only slightly when nudged, about 45 minutes. Let cool on a wire rack. Top with the cranberries.
Up To 2 Months Ahead: Make the dough. Store in an airtight container in the freezer. Thaw overnight in the fridge before rolling.
1 Day Ahead: Make the cranberries. Let stand, uncovered, at room temperature. Roll out and crimp the crust. Cover and refrigerate.
8 Hours Ahead: Bake the pie. Let stand at room temperature.
Thanksgiving recipes for planners and procrastinators here.