Preheat oven to 350. Butter 8x8" metal baking pan. Bring 1 1/2 cups water to simmer in medium saucepan. Add dates, simmer until very soft and thick, stirring occasionally, about 10 minutes. Cool at room temperature. Stir in vanilla.
Combine flour, sugar, oats, cinnamon, baking soda and salt in large bowl, stir to blend. Add butter. Using fingertips, rub in until moist clumps form. Press half of the oat mixture evenly over bottom of prepared pan. Spread date mixture over. Sprinkle with remaining oat mixture, press gently to adhere. Bake until brown at edges and golden brown and set in center, about 40 minutes. Cool completely in pan on rack. Cut into bars and serve.