1Heat oven to 350°F. Spray 9-inch square pan with cooking spray.
2In large bowl, beat 2 cups of the Bisquick mix, the milk, granulated sugar, melted butter, vanilla and egg with electric mixer on low speed 30 seconds. Beat on medium speed 2 minutes. Pour into pan. In small bowl, toss frozen raspberries with flour. Sprinkle over batter.
3In small bowl, mix remaining 1/2 cup Bisquick mix and the brown sugar. Cut in 3 tablespoons butter, using pastry blender or fork (or pulling 2 table knives through mixture in opposite directions), until crumbly. Stir in pecans. Sprinkle over batter.
4Bake 35 to 40 minutes or until toothpick inserted in center comes out clean. Cool completely in pan on cooling rack, about 1 hour. Cut into 3 rows by 3 rows. Sprinkle with powdered sugar.