Pre-heat the oven to 180°C fan / 400°F / Gas 6.
In a medium mixing bowl or stand mixer fitted with a whisk attachment, beat the egg yolks, sugar and vanilla, until pale and fluffy.
Add the flour, baking powder, salt, oil and milk to the bowl. Mix together thoroughly.
In another large mixing bowl, whisk the egg whites until frothy. Add the sugar and whisk until soft peaks form.
Gently fold the egg whites into the cake batter and then pour the batter into a 20 x 30cm (8x12inch) ceramic baking dish. There is no need to grease your dish or pan when making a chiffon cake, otherwise the cake tends to collapse at the edges.
Baking: Place in the oven and bake for 16-18 minutes or until a wooden pick inserted in the centre comes out clean. (The cake should spring back when gently poked with your finger.)
Once the cake has cooled, gently run a knife around the edges of the dish/pan to release the cake.
Macerated strawberries: Clean and slice the strawberries, place them in a bowl and add the sugar. Leave to macerate while you make the cream.
Mascarpone cream: In a large bowl or in a stand mixer with the whisk attachment, whisk the cream until it reaches soft peaks. Add the mascarpone and the sugar and whisk until completely smooth and creamy.
Spread the cream evenly over the cake and then spoon over the macerated strawberries. Finally, decorate with mint and serve.