Strawberry shortcake roulade

Ingredients

• 3 large eggs, at room temperature and separated
• 2 tablespoon vegetable oil
• 2 tablespoon milk
• 1 teaspoon vanilla extract
• 1/2 cup caster sugar
• 1 tablespoon lemon zest
• 1/2 cup plain flour
• 1 level tbsp cornflour
• 1/2 teaspoon baking powder
• pinch of salt
• Filling
• 250 gram fresh strawberries, hulled and sliced, plus extra
• 1 tablespoon sugar
• small squeeze lemon juice
• 200 millilitre cream
• 1 tablespoon sour cream
• 1/2 teaspoon vanilla extract
• 1/4 cup icing sugar, plus more for dusting