Preheat oven to 325 degrees Fahrenheit.
Combine cream cheese and jam and whisk to mix thoroughly.
Line a baking tray with parchment paper or use the same parchment sheet of the pastry. Lay the pastry on the paper as smooth as possible maintaining it's rectangular shape.
Fold the corners of the pastry about 1" inwards and press down gently to seal it.
Score the edges (near the fold) with blunt knife without cutting into the pastry. Score randomly all over the pastry too so that it doesn't rise while baking.
Apply cream cheese all over the pastry and spread the blueberries over it making sure there are no gaps in between.
Bake for 25 minutes or until the pastry looks sufficiently golden brown in color.
Remove from oven and cool the tart. Sprinkle powdered sugar with a sitter all over the pastry.
Cut the tart in 8 equal parts and serve cold or with icecream.
