Preheat the oven to 350ºF (177ºC).

Spray a casserole dish with nonstick spray and set aside.

In a medium bowl, combine brown sugar, flour, melted butter, and salt. Toss with a fork to combine.

Add the chopped pecans, then stir again until everything is thoroughly combined. Set aside.

Peel the sweet potatoes and cut into 1-2 inch chunks.

Bring a large pot of water to a boil, add the cut sweet potatoes, and boil for 15-20 minutes, or until fork-tender. Drain and allow to cool for 15 minutes.

Once cooled, mash the sweet potatoes to your desired consistency.

Add granulated sugar, melted butter, eggs, vanilla extract, and salt to the mashed sweet potatoes. Stir to combine.

Pour the sweet potato mixture into the prepared baking dish.

Sprinkle the pecan topping evenly over the top of the sweet potatoes.

Bake the casserole for 30-35 minutes. Allow to cool slightly before serving.