1. Preheat the oven to 350F/180C. Lightly oil and line a 10 x 8 inch / 25 x 20 cm shallow, rectangular baking pan with parchment paper.
2. Cream the butter and sugar together in a bowl until light and fluffy, then gradually beat in the eggs, adding a little flour after each addition.
3. Add all the remaining ingredients, except the slivered almonds. Spoon the mixture into the prepared pan and smooth the top. Sprinkle with the slivered almonds.
4. Bake in the preheated oven for 35-45 minutes, or until the mixture is cooked and a skewer inserted into the center comes out clean.
10 mins to prepare, 35-45 mins to cook and cool
Serves: 14-16 bars