Homemade Strawberry Shortcake Rolls

Let's get started!

1. Sponge Cake: Preheat the oven the 325F°. Line a lightly oiled half sheet pan with parchment. Place an extra tall half sheet pan in the oven and fill half to 3/4 full with warm water in the oven while preheating. 
2. In a medium sauce pan, add the vegetable oil and heat for about 30 seconds to warm. Add the cake flour and cornstarch, then whisk until smooth. Add the milk, then turn the heat to medium. Whisk until thickened, then transfer the roux mixture to a medium bowl.
3. Into the roux mixture, add the yolks, salt and vanilla then whisk until smooth. 
4. In the bowl of a stand mixer, add the egg whites and cream of tartar. Whip until foamy. Then slowly add the sugar (about 1 minute). On high speed, whip until stiff peaks. 
5. Add 1/3 of the meringue to the yolk mixture and fold until combined. 
6. Add all of the egg yolk mixture to the remaining meringue and gently fold until combined.
7. Pour the batter into the prepared pan and smooth flat with an offset spatula.
8. Place in water bath in the oven (add more water if needed), and bake at 325°F for 6-10 minutes, then raise heat to 340°F for 4 minutes, or until golden brown on top. 
9. Remove only the cake pan from oven and allow to cool.
10. Ermine Buttercream: In a large saucepan, pour in the flour and sugar. Whisk over medium heat for 30 seconds. 
11. While whisking constantly, slowly pour in the milk. Continue to stir while it cooks, until a thick custard texture.
12. Pour into a bowl and cover with plastic wrap, pressing it onto the surface. Let cool to room temperature. 
13. In a stand mixer, place the softened butter and cream on medium-high until it becomes fluffy and pale, about 3 minutes.
14. On medium speed, start adding the custard mixture 2 tablespoons at a time, then add the vanilla and salt. Whip until stuff peaks, about 2-3 minutes.
15. Strawberry Filling: In a medium saucepan, add the cornstarch and water. Stir until no lumps remain.
16. Add the strawberries, sugar, lemon juice and citric acid, and cook until thickens stirring constantly, about 5 minutes.
17. Turn off the heat and mix in the red food coloring. Let cool, then scoop into a piping bag fitted with a small basket weaving tip.

Time to Assemble!

1. Cut the cake into eight (8) 5 1/2"x4" rectangles.
2. On one side of the cakes, spread a thin layer of buttercream. Pipe 6 long flat lines of strawberry filling on top.
3. Gently roll up cakes, and chill in the refrigerator for 30 minutes. 
4. Brush the thinned, melted white chocolate on a parchment lined baking sheet. Place the rolls on top and let set. Trim off excess white chocolate.