Toast the chopped pecans (optional): For extra toasted flavor, toast the chopped pecans. (Do not toast the pecan halves going on top of the pie; they will toast up while the pie bakes.)Oven method: Spread pecans in one layer on a baking sheet and bake at 350°F for 7-10 minutes, stirring after about 5 minutes.Stovetop method: Add pecans to a dry skillet and heat over medium. Once the pan has heated, you'll toast them for about 3-5 minutes, stirring constantly, until they smell fragrant and have darkened a little. Prep: Preheat oven to 350°F. The rack should be in the middle of the oven.
Melt the butter: In a saucepan over medium heat, combine the vegan butter and brown sugar. Heat just until both are melted together, then remove from heat.
Mix the gooey filling: To a mixing bowl, add the maple syrup, kosher salt, vanilla extract, plant milk, cornstarch, and flour. Whisk vigorously until there are no lumps. Pour in the butter and brown sugar mixture and stir to combine.
Add pecans: Fold in the 2 cups chopped pecans, and then pour this mixture into your pie crust. Arrange the pecan halves on top for a decorative finish.
Important! Place the pie on a baking sheet in the oven to catch any drips of bubbly pie filling or butter from the crust. You do not want any landing on the bottom of your oven! (Speaking from experience.)
Bake: Bake for 50-55 minutes. Loosely tent the pie with a sheet of aluminum foil after about 30 minutes to shield the crust and the pecan halves from getting too dark. (You may need to do this step a few minutes earlier if you par-baked the crust.)
Check for doneness: When the pie is done baking, the filling will appear slightly bubbly and may still be a little jiggly. That's ok; it will set as it cools! Carefully remove the pie from the oven and place on a wire rack.
Cool: Personally I prefer to wait for the pie to cool entirely to room temperature before serving. I bake it the night before I plan to serve it so it can cool overnight. If you will serve it on the same day, I recommend cooling for at least 1 hour so that the filling has a chance to fully set.
Storage: I find this pie stores perfectly on the counter (no need to refrigerate) for up to 5 days. Just make sure to keep it covered.