Linzer Cookies

Ingredients

• 1 tbsp icing sugar
• 225 g raspberry jam (or use Nutella or lemon curd)
• 175 g soft butter, plus extra for greasing
• 85 g blanched hazelnuts (or use ground almonds, see Tip)
• 100 g caster sugar
• 1 egg
• 1 tsp vanilla extract
• 200 g plain flour, plus extra for dusting
• 1/4 tsp salt
• 1/2 tsp ground cinnamon
• 1 small orange, grated zest only (optional)