Layered jelly roll cake (recipe)

Yesterday's cake was in my mind for some time, the components aren't difficult, the only thing I had to decide was whether I would make a "bombe" or build it in a spring form.

Recipe cake layers top and bottom
4 eggs
7 tbs hot water
200 gr sugar
1 package vanilla sugar (1 tsp vanilla extract)
150 gr ap flour
60 gr corn starch
1 heaped tsp baking powder

In the bowl of your mixer, combine eggs and water and whisk on high speed for 1 minute. Add sugars and whisk for another 3 minutes. Mix dry ingredients and sift half of it into the egg creme. Whisk on low until incorporated, add the second half and incorporate. Don't mix too long.
Pour 3/4 of this batter on a sheet pan lined with parchment paper, spread to corners. 1/4 of the dough goes into a 22 cm springform pan (bottom lined with paper).
Bake for 10-15 minutes on 200C (sheet) and 15-20 minutes (springform).

Straight from the oven, turn the sheet cake upside down onto a towel generously sprinkled with powdered sugar. Carefully remove paper. While still warm, spread with jelly and carefully roll cake from long end. Cool on wire rack at least 30 minutes. (I used a slightly damp towel to keep it from unrolling. When cooled, slice into approx. 16 1" slices. Remove bottom layer from spring form and set aside to cool on a wire rack.

Recipe bavaroise filling
1 tbs gelatine powder (6 sheets gelatine)
3 tbs cold water
25 gr corn starch
200 ml white wine (would sub by fruit juice next time)
60 gr sugar
3 egg yolks
juice of 1 lemon

500 ml whipping cream
150 gr greek yoghurt

Mix powder with gelatine, set aside to soften. In a medium saucepan mix egg yolks, sugar, juice and wine and heat on low/medium, whisking continuously until it starts to thicken, then add the gelatine mixture. Pay attention, due to the lemon juice this comes together very, very quickly! Set aside to cool.
Whip cream to medium peaks and fold in yoghurt. Fold this mixture into the cooled gelatine cream. Use right away, don't let it set too much.

Recipe gelatine mirror
1 package clear cake glaze
25 gr sugar
250 ml white wine (I used packaged clear fruit juice)
-if you don't have access to this cake glaze you could use the recipe for the mirror- as well.

Assembly
Now this is one to pay attention to, I really thought it over but the best way to do it is build it top side down, that way you´ll ensure the top layer is straight and level. In short hand: jelly roll slices go in first, bavaroise is next, top with cake layer, cool and unmold. Finish with mirror and decorate.

~ Prepare a larger spring form (26cm), oil the sides with a vegetable oil, line the base with waxed paper.

~ Arrange the jelly roll slices on the base, starting on the rim, working your way to the center. Make sure the slices are firmly pressed together, don´t leave any gaps.

~ Pour the bavaroise in (save about a cup of bavaroise for piping a rim around the cake layer), wiggle a bit to get rid of air holes and ensure an even smooth layer.

~ Arrange your base cake layer on top of the bavaroise, lightly press down, leaving a rim.

~ Pipe a ring of bavaroise around the cake layer. Smooth with the back of a teaspoon.

~ Refrigerate and let cool and firm up for about two hours or more.

You won´t be able to move this cake around once it´s turned so use your serving platter, place it on top and turn upside down. Open ring, carefully slide it off, remove springform base. Now, place the ring around the cake again, ever so careful, snap it close and pour the thickened (syrupy not jellied) finish over the top of the cake. Refrigerate again to let it set.

Verdict and Filling: I used the wine-yoghurt recipe for the filling, but frankly I thought it was a bit disappointing (I might have picked the wrong wine, and perhaps should have used a dessert wine instead) and I think a minority of the taste/panel agreed. I didn´t like the slight bitter (not tart) flavour and would prefer a tart yoghurt bavaroise, or the bavarian we used in the Strawberry Mirror Cake, recipe can be found here.

My preference for the filling is a yoghurt based bavarian like this which I also used in the second strawberry mirror cake I made:

150 gr yoghurt/quark
150 gr fruit puree/fruit juice (or fresh pressed citrus juice like lemon or lime)
200 gr powdered sugar
500 ml whipping cream
6 sheets gelatine

Mix yoghurt, juice, sugar. Soften gelatine sheets in cold water for 5 minutes, squeeze to get rid of excess water and dissolve in 4 tbs of hot water. Whisk gelatine mixture and yoghurt mixture. Whip cream to soft peaks and fold into yoghurt/gelatine mixture.
Use as directed in the recipe.

Question: would you like to read this recipe in Dutch as well? Let me know please!