Prepare your baking tin by lightly greasing it with butter and lining the bottom with baking paper (I used rectangular baking tin 28x18cm).All the ingredients should be at room temperature.
Preheat the oven to 180C/375F/Gas Mark 4.
In a large bowl, mix together flour and baking powder. Alternatively, you can sieve both into the bowl. Set aside.
In another bowl whisk together egg, milk, oil, zest & lemon juice, sugar and almond extract (if using). Make sure you whisk only until combined, do not overmix.
Add ground almonds, sieved flour and baking powder and mix gently with wet ingredients only until combined.
Pour the cake batter onto prepared baking tin and arrange plum halves (cut side up) on top of the batter.
Amaretti Biscuits Topping
In a small bowl mix crushed amaretti biscuits with softened butter (you will get quite a sticky mixture) and dot it evenly over the top of the cake.
Bake in the preheated oven for about 50 min or until the skewer inserted into the cake comes out clean.
Once baked make sure you leave the cake to cool down in its tin for 10-15 minutes before taking it out onto a rack to cool completely.
Serve sprinkled with some icing sugar or slightly warm with vanilla ice cream!
Nutritional information is approximate, per 1/8 of the cake and should be treated as guideline only.
Store this plum and almond cake in the airtight container on the kitchen counter for 2-3 days (depending on how hot your kitchen is). If worried that plums might start to go bad simply pop it in the fridge and warm up gently in the microwave before serving.
This cake is also freezer friendly. Simply wrap it tightly in the baking paper and some aluminium foil and pop in the freezer for up to 3 months.