Method

• 1.
  Line a baking tray with baking paper. Place 95g raw sugar in a pan over medium heat. Cook, swirling pan, for 8-10 minutes until golden, add 1/2 cup (50g) walnuts to pan, then pour onto tray. Set aside to cool completely. Crumble into large pieces.
• 2.
  To make sponge, preheat oven to 180°C. Grease and line a 3cm deep 24cm x 34cm baking tray with baking paper, then grease paper with butter. Sift over extra 1 1/2 tbs icing sugar. Whiz remaining 1/2 cup (50g) walnuts in a food processor to a fine powder. Beat the egg yolks and remaining 1/4 cup (55g) raw sugar in a bowl until thick and pale. Stir in vanilla and walnut meal, then sift in flour, baking powder and 1 tsp salt. Fold to combine.
• 3.
  Using electric beaters, whisk the eggwhites in a bowl until stiff peaks form. Fold 1 tbs into cake mixture to loosen, then fold in remainder. Pour mixture onto lined tray and level the surface. Bake for 8-10 minutes until cooked through and light golden. Cool sponge on tray for 5 minutes, then turn out onto a clean tea towel laid out on a work surface (leaving the baking paper on the sponge). Rest for a further 5 minutes. While still warm, using the tea towel, gently roll up from the long end, like a swiss roll. Leave for 5 minutes, then unroll and remove paper. This will make it easier to roll up later.
• 4.
  Meanwhile, whisk cream to soft peaks, then fold through orange zest. In a separate bowl, sift remaining 1 1/4 cups (150g) icing sugar, then stir in 1 1/2 tbs orange juice to give a thick pourable icing.
• 5.
  When sponge is cool, spread over marmalade, leaving a 1cm border at the long end closest to you, then spread with two-thirds orange cream leaving a 2cm border on the long sides. Carefully roll up sponge, and place on a serving plate. Chill for 15 minutes.
• 6.
  Drizzle with icing and top with walnut praline. Serve with remaining cream.