CRUST: 1-1/2 cups old-fashioned oats 1-1/2 cups all purpose flour 1 cup firmly packed brown sugar 1/2 teaspoon baking soda 1 cup (2 sticks) chilled unsalted butter, cut into small pieces For filling: Combine all ingredients in medium saucepan. Bring to simmer, stirring to dissolve sugar. Simmer 1 minute. Puree mixture in processor. Cool completely. For crust: Preheat oven to 350°F. Butter 9x13-inch baking pan. Mix oats, flour, sugar and soda in medium bowl. Add butter and rub with fingertips until mixture resembles coarse crumbs. Firmly press half of crumb mixture into bottom of prepared pan. Spread filling over crust. Sprinkle remaining crumb mixture over filling. Bake until topping is golden brown, about 38 minutes. Cool in pan. (Can be prepared 1 day ahead. Cover and let stand at room temperature.) Cut into squares. dess 128