Gluten-free Coffee and Walnut Cake Traybake

Cake

• 80 g walnut halves
• 230 g unsalted butter, diced
• 230 g granulated sugar
• 4 large eggs
• 4 Tbsp instant coffee granules, mixed with 2 Tbsp boiling water
• 230 g gluten-free self-raising flour

Candied Walnuts

• 100 g granulated sugar
• 1050 g water
• 1 ½ Tbsp instant coffee granules, mixed with 1 Tbsp boiling water
• 200 g walnut halves
• 15 g vinegar

Icing

• 200 g granulated sugar
• 1 Tbsp instant coffee granules, mixed with 1 Tbsp boiling water
• 25 g water