Preheat oven to 150°C (130°C fan-forced), lightly grease a deep 20cm x 8cm spring form tin and line the base with baking paper. Line a baking tray with baking paper.
Combine the verjuice and caster sugar together in a small saucepan over a low heat, stirring until sugar dissolves. Increase heat, bring to the boil and cook for 5 minutes. Remove from heat. Place strawberries on prepared baking tray and pour over syrup.
Place in preheated oven, cook for 1 ½ hours or until the strawberries have turned a deep red and shrivelled slightly. Remove from oven and set aside for later. Increase oven temperature to 180°C (160°C fan-forced).
Place pastry on a lightly floured kitchen work surface. Cut a 20cm round from the far end of the sheet and then cut three 8cm wide x 25cm long strips from the rest of the sheet, for the sides. Cut 1cm incisions along one side of each pastry strip (as you would for baking paper) to help line the side of the tin. Gently line the tin with the pastry strips, pushing the cut edges 1cm across the base. Brush the three sides joins with egg glaze to seal and also the cut edges at the base.
Gently place the pastry round over the cut edges, at the base of the tin, pressing gently to seal. Cover with plastic wrap and chill in the refrigerator for 30 minutes.
To blind bake the pastry case, line the pastry case with baking paper. Cover paper with baking weights or a dried pulse (eg. chickpeas) and fill to the top of the tin, to help support the sides and weigh the base down during cooking.
Place tin in preheated oven and bake for 15 minutes. Remove tin from oven, check pastry is lightly golden before removing beans and baking paper. Return tin to oven and cook for a further 10 minutes. Remove from oven and allow to cool.
For the filling, place the cream cheese, sugar, eggs vanilla bean paste and cooked strawberries in syrup together in a food processor and blitz until smooth and well combined. Add the mascarpone and pulse until just combined.
Pour into the prepared pastry case and bake in preheated oven for 1 hour or until the centre has a slight wobble. Remove from oven and allow to cool for 15 minutes.
Meanwhile make the sour cream topping by combining ingredients together in a small mixing bowl, stirring until combined.
Gently spread over the top of the cheesecake. Return cheesecake to oven and cook for a further 10 minutes, to help set the topping. Turn the heat off and leave cheesecake in oven to cool, with the door ajar to prevent cracking.
Refrigerate cheesecake for at least 4 hours, preferably overnight before serving.