Preheat the oven to 350 degrees and grease a 9 x 13 pan with nonstick cooking spray. Boil sweet potatoes until fork tender, drain and place back into pot.
Add in butter, milk, sugar, vanilla, salt and eggs to the sweet potatoes. Using a masher mix until smooth and creamy.
Layer the sweet potatoes into the bottom of the prepared dish.
Top with the streusel and bake for 25-30 minutes or until golden brown. Serve immediately.
Streusel Topping
Combine all of the ingredients in a medium bowl. Set aside.