1Heat oven to 350°F. Spray 13x9-inch pan with cooking spray.
2In large bowl, stir together yogurt, 1 1/2 cups of the granulated sugar, the melted butter and vanilla until well combined. Mix in eggs, 1 at a time, until well blended. Add flour, baking powder and salt; beat with rubber spatula or wooden spoon until smooth.
3Pour batter into pan, spreading evenly. Stir strawberry jam until smooth. Drop by teaspoonfuls on top of batter. Sprinkle with strawberries and remaining 2 teaspoons granulated sugar.
4Bake 40 to 50 minutes or until toothpick inserted in center comes out clean. Cool 20 minutes. Sprinkle with powdered sugar.