Preheat oven to 350°F. Mash the sweet potatoes and combine with all the other filling ingredients. Pour into the pie shell and bake until firm, about 35-40 minutes.
Meringue: Add the salt, vanilla and lemon juice to the egg whites. Beat until foamy. Add the 6 Tbsp sugar, 1 at a time. Beat until the sugar dissolves and the mixture forms stiff peaks.
Praline topping: Combine the brown sugar, corn syrup, butter and vanilla in a medium saucepan. Cook and stir on medium heat until the butter is melted and the mixture is blended. Remove from heat.
Spoon dollops of meringue in a ring around the outside edge of the pie. Sprinkle the pecans over the center of the pie. Drizzle all or part of the praline topping over the nuts, as desired.
Bake for 15 minutes or until golden brown. Cool to room temperature before serving. Refrigerate leftover pie.