Preheat oven to 350°F (175°C). Line a 10×15 inch (25×38 cm) jelly roll pan with parchment paper and lightly grease. Sprinkle a small amount of flour or leave the parchment ungreased for easy release.

In a medium bowl, whisk together the 4 egg yolks and 1/2 cup (100 g) of the granulated sugar until pale and slightly thickened, about 2 to 3 minutes. Stir in the vanilla and oil.

Gently fold the sifted cake flour and salt into the yolk mixture until just combined; do not overmix.

In a clean bowl, beat the 4 egg whites to soft peaks. Gradually add the remaining 1/4 cup (50 g) sugar and beat until glossy, medium peaks form.

Fold one third of the beaten egg whites into the yolk batter to lighten it. Then gently fold in the remaining whites until no large streaks remain.

Spread the batter evenly in the prepared pan. Bake 10 to 12 minutes, until the top is golden and the sponge springs back lightly when touched.

Immediately after removing from the oven, invert the sponge onto a clean kitchen towel dusted with powdered sugar. Peel off the parchment, and starting from the short side, roll the cake and towel together into a tight spiral. Let it cool completely rolled up.

Mash the ripe bananas with lemon juice until mostly smooth.

In a bowl, beat the softened cream cheese with powdered sugar until smooth. Whip the heavy cream to soft peaks, then fold into the cream cheese. Stir in mashed banana and cinnamon if using.

Carefully unroll the cooled cake. Spread the banana filling evenly, leaving a 1/2-inch border. Roll the cake back up without the towel.

Wrap the roll in plastic wrap and refrigerate at least 1 hour to firm up. Dust with powdered sugar and garnish with banana slices or chocolate before slicing into 1-inch slices. Chill any unused slices.