1 ½ cups water
1 ½ cups chopped pitted dates
1 teaspoon vanilla extract
1 ½ cups all purpose flour
1 cup (packed) dark brown sugar
1 cup old-fashioned oats
1 ½ teaspoons ground cinnamon
½ teaspoon baking soda
½ teaspoon salt
¾ cup (1 ½ sticks) unsalted margarine diced, room temperature
Preheat oven to 350°F. Butter 8×8-inch metal baking pan. Bring 1 ½ cups water to simmer in medium saucepan. Add dates; simmer until very soft and thick, stirring occasionally, about 10 minutes. Cool to room temperature. Stir in vanilla.
Combine flour, sugar, oats, cinnamon, baking soda and salt in large bowl; stir to blend. Add margarine. Using fingertips, rub in until moist clumps form. Press half of 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 edge and golden brown and set in center, about 40 minutes. Cool completely in pan on rack. Cut into bars and serve.