Chiffon cake

1. Preheat oven to 350°F / 180°C and prepare 3 unlined 6 inch / 15 cm diameter aluminum cake pans. (see notes for baking in 2 batches) 
2. In a bowl, mix together the dry ingredients, cake flour, salt and baking powder and sift at least twice and set aside.
3. In another bowl, whisk together the egg yolks with the vegetable oil, 3/4 of the sugar, vanilla and milk. 
4. Add the dry ingredients to the liquid ingredients and whisk until smooth.
5. Place the egg whites in the bowl of a hand mixer or your stand mixer fitted with the whisk attachment.
6. Beat on medium slow speed for 3 - 4 minutes until bubbles appear.
7. Then add the cream of tartar and remaining sugar and beat on high speed for another 3 - 4 minutes until you have a firm but not too stiff meringue.
8. Add a small amount of meringue to the bowl containing the other ingredients and mix quickly to loosen the mixture.
9. Then gently fold in the rest of the meringue with a spatula, working in circular motions from the center to the outside until you have a smooth mixture.
10. Pour the batter into the 3 unlined molds and run a knife through to remove any air pockets.
11. Bake in the oven on the middle rack for 30 to 35 minutes without opening the oven door until golden brown on top. (Check for baking by sticking a toothpick in the center and it should come out clean) 
12. Remove the pans from the oven and let them cool completely, upside down, for at least 1 1/2 hours. 
13. Turn out the cakes by gently running a knife around the edges. 
14. Cover the cakes with plastic wrap and place in the refrigerator until ready to assemble.

Strawberry Filling:

1. In a medium bowl, place the sliced strawberries with the granulated sugar and mix.
2. Let stand in the refrigerator for about 30 minutes.
3. Remove excess juice before assembling.

Mascarpone whipped cream:

1. Place the cold heavy cream, cold mascarpone cheese, powdered sugar and vanilla in a large bowl.
2. Beat with an electric whisk or your stand mixer on medium speed for about 4 minutes until you have a thick, stiff whipped cream. 

Assembly of the layer cake:

1. Place a cake board on your turntable and place a first layer of cake.
2. Add a small amount of mascarpone whipped cream and hollow out the center to put the strawberry filling in.
3. Cover the strawberries with whipped cream to enclose them in the center.
4. Place a second layer of cake and repeat the last step then finish with the last layer of cake.
5. Cover the entire cake with the mascarpone whipped cream and smooth with a spatula or an icing smoother.
6. Decorate the top with the remaining whipped cream and a piping bag and add fresh strawberries.
7. Place the cake in the refrigerator for about 1 hour before serving with a sprinkling of confectioners' sugar.