Preheat oven to 350°F. Line a 8x8-inch pan with parchment paper and set aside.
Combine the box of cake mix, 1/3 cup oil and 2 eggs in a large bowl. Stir together until combined. It will be a thicker mixture.
Press the dough into the baking dish with the palm of your hands. Bake for 18-20 minutes, or until a toothpick comes clean. Let cool.
In a medium sized bowl, whisk together 2/3 cup powdered sugar, 2 Tablespoons jam, 2 Tablespoons heavy cream and pinch of salt. Whisk until smooth. Add more cream (or milk) as needed to thin it out. It should be the consistency of glue.
Spread evenly on top of cooled brownies. Then slice into 16 bars.
Notes
Variation: You may also mix in a 1/2 cup white chocolate chips if you’d prefer. If you'd prefer them less sweet, feel free to omit the glaze.Storage: Store in an airtight container for 3 days or freeze up to 3 months. Thaw overnight in the refrigerator before enjoying, or leave at room temperature.