Place half of the cake cubes trifle bowl. Instructions. Arrange 1/3 of the strawberries around sides of bowl and on top of cake. In a mug, combine all dry ingredients for cake. To a large mixing bowl add the flour, seeds, salt, sugar & baking soda and mix together. Top with half of the custard. Refrigerate for 2 hours before serving. Stir until mixed thoroughly. Cut into one inch squares. Add wet ingredients. Assemble Trifle: Brush cooled cake with sherry or orange liquor. Top with coconut whipped cream and remaining berries. Mix well. Place in the microwave for 3-4 minutes. Pour in the milk mix, oil and vanilla and mix together until the cake batter forms. Repeat layers once.