Apple and custard streusel slice

Method

• Step 1
  Make Custard: Combine custard powder and sugar in a small saucepan. Gradually stir in milk until smooth and combined. Place over medium-high heat. Cook, stirring, for 5 minutes or until mixture just starts to boil and thickens. Remove from heat. Transfer to a heatproof bowl. Cover surface with plastic wrap. Cool. Refrigerate for 1 hour or until cold.
• Step 2
  Meanwhile, make Streusel: Using a food processor, process flours, sugar and cinnamon together. Add butter. Process until mixture comes together and forms a dough. Wrap in plastic wrap. Freeze for 1 hour.
• Step 3
  Preheat oven to 180C/160C fan-forced. Grease a 20cm x 30cm lamington pan. Line base and sides with baking paper, extending paper 3cm above edges of pan.
• Step 4
  Place butter, sugar, flour and egg in a bowl. Stir well to combine. Press mixture over base of prepared pan. Bake for 10 to 15 minutes or until golden. Cool completely.
• Step 5
  Drain apple on paper towel. Pat dry. Spread custard over prepared base. Sprinkle with apple. Remove streusel from plastic. Coarsely grate over slice. Sprinkle with almonds. Bake for 25 to 30 minutes or until golden. Cool in pan. Serve cut into bars.