Preheat oven to 400 degrees. Roll pie crust into glass pan. Fold crust to desired adornment.
Slice the peeled and pitted peaches to desired size. Place peach slices in a bowl. Combine flour, sugars, cinnamon, and vanilla. Mix thoroughly. Using a slotted spoon, spoon into pie crust, leaving behind excess juices.
In small bowl, combine brown sugar, flour, walnuts, cinnamon, and melted butter. Consistency will be clumpy. Sprinkle over top of pie.
Place pie in oven to bake for 20-25 minutes. At the 25 minute mark, I place a pie crust protective covering to prevent it from burning. Reduce oven heat to 375 and bake for additional 20-25 minutes.
Remove pie from oven. Let cool for 5-6 hours in refrigerator before cutting into.