Preheat oven to 350 degrees F. Grease 13- by 9-inch metal baking pan.

On waxed paper, combine flour, cocoa, baking powder, and salt. In 3-quart saucepan, melt butter over medium-low heat. Remove saucepan from heat; with wire whisk, stir in sugar. Add eggs, 1 at a time, beating well after each addition. Stir in jam and vanilla, whisking until well mixed. With spoon, stir flour mixture into chocolate mixture just until blended. Spread batter in pan.

Bake brownie 30 to 35 minutes or until toothpick inserted 2 inches from edge comes out almost clean. Cool in pan on wire rack.

When cool, cut brownie lengthwise into 6 strips, then cut each strip crosswise into 6 pieces.