Mini Classic Polish "torts"

Name: Mini Classic Polish "torts"
Prep time: 30 min
Cook time: 2 h 30 min
Total time: 2 h 30 min
Yield: 4 portions
Ingredients: butter; 120 g plain flour; 4 eggs; 120 g white sugar; 1 tsp natural vanilla extract; ½ tsp baking powder; 2 pinches sea salt; 250 g fresh blueberries; 100 g jam sugar; 50 g water; 1 ½ tsp freshly squeezed lemon juice; 1 tsp vegetable oil; 70 g water; 20 g freshly squeezed lemon juice; 300 g fresh mixed berries; 250 g mascarpone cheese; 300 g pouring (whipping) cream; 20 g icing sugar; 1 tsp natural vanilla extract; fresh mixed berries; fresh mint