In a medium saucepan, add raisins, water and white sugar. Cook over medium heat for 10 minutes, until raisins become plump. Take off heat and add a T each of flour, vanilla and butter.
While filling is cooking mix together in mixing bowl the brown sugar, margarine, oatmeal, flour and soda.
Spread ½ oatmeal mixture in a 9 x 13 baking dish, sprayed with cooking spray. Spread/pour onto mixture the filling; spread the rest of oatmeal mixture over top of filling. Bake 30 minutes at 350 degrees.
Recipe by The Gingham Apron at https://www.theginghamapron.com/grandmas-raisin-bars/