Method
1
Preheat the oven to 100°C.
2
Line a baking sheet with parchment paper.
3
Beat the egg whites until foamy.
4
Add the granulated sugar a spoonful at a time while beating.
5
Beat until the meringue is glossy and holds stiff peaks.
6
Fold the cornstarch into the meringue.
7
Spoon the meringue into a piping bag fitted with a plain round tip.
8
Pipe 12 small domes onto the prepared sheet for mushroom caps.
9
Pipe 12 short tapered stems onto the sheet.
10
Dust the caps lightly with cocoa powder.
11
Bake the meringues for 75 minutes.
12
Turn off the oven and leave the meringues inside with the door slightly open until cool.
13
Preheat the oven to 190°C.
14
Line a 30-by-40 cm baking pan with parchment paper.
15
Whisk the flour, cocoa, baking powder, and salt in a bowl.
16
Beat the eggs and sponge sugar until pale, thick, and doubled in volume.
17
Sift the dry ingredients over the egg mixture.
18
Fold the dry ingredients into the egg mixture.
19
Fold in the melted butter.
20
Spread the batter evenly in the prepared pan.
21
Bake the sponge for 10 to 12 minutes, until it springs back lightly when touched.
22
Lay a clean kitchen towel on the counter.
23
Dust the towel lightly with icing sugar.
24
Turn the warm sponge onto the towel.
25
Peel away the parchment paper.
26
Roll the sponge up gently from a short end with the towel inside.
27
Leave the rolled sponge to cool completely.
28
Melt the 50 g of chocolate in a heatproof bowl.
29
Dab a little melted chocolate onto the flat side of each meringue cap.
30
Press a meringue stem onto each cap to assemble the mushrooms.
31
Chill the remaining melted chocolate until thick enough to drizzle.
32
Whip the filling cream with the icing sugar and vanilla until it holds soft peaks.
33
Unroll the cooled sponge carefully.
34
Spread the whipped cream evenly over the sponge.
35
Roll the sponge up again without the towel.
36
Place the roll seam-side down on a serving platter.
37
Heat the ganache cream in a small saucepan until steaming.
38
Pour the hot cream over the chopped chocolate.
39
Let the mixture stand for 2 minutes.
40
Stir the ganache until smooth.
41
Cool the ganache until spreadable.
42
Spread the ganache over the log.
43
Drag a fork through the ganache to make bark-like lines.
44
Arrange the meringue mushrooms on top of the log.
45
Drizzle the reserved melted chocolate over the mushroom caps.
46
Dust the log lightly with icing sugar just before serving.
47
Arrange the cranberries around the log.