Preheat oven to 180c. Line a 2lb loaf tin with baking parchment.
First make your frangipane. Beat the butter and sugar together for a few minutes until light and creamy (you can do this in a mixer or by hand). Add the egg and beat again for a minute. Add the flour, baking powder, ground almonds and almond extract and mix for 2 more minutes. Cover and place in the fridge whilst you make the chocolate banana cake.
In a mixer, whisk the egg, oil and sugar until combined, then add in the bananas. Whisk again until the banana breaks down and you’ve got a slightly lumpy liquid.
Add in the flour, sieved cocoa powder, baking powder and bicarbonate of soda. Gently stir into the banana mixture using a silicone spatula or wooden spoon until combined. Then add in the chocolate chips and gently and stir again.
Pour a third of the chocolate mixture into into the loaf tin, then dot half of the frangipane in little lumps on top. Pour another third of chocolate mix on top, then add in the remaining frangine in little dots. Use a cocktail stick to give the frangipane a couple of little swirls into the chocolate mixture. Pour the remaining chocolate mixture on top. Place in the oven to cook for 40-50 minutes (check it’s done after 40 minutes by inserting a metal skewer in the cake, if it comes out clean, it’s cooked). You may need to cover the cake with a bit of foil if it needs to cook for more than 40 minutes.
Take the cake out of the oven and allow to cool in the tin for 10 minutes, before removing from the tin and allowing to cool completely on a cooling rack.
Whilst the cake is cooling make the frosting and candied nuts.
For the frosting, whisk together the confectioners sugar, 2tbsp cream, the vanilla extract and half the almond extract. You're looking for a spreadable consistency, so you need to ensure it's quite thick. Add a little more cream if required. Taste and then add the remaining almond extract if you want a stronger almond taste. Put to one side.
Next make your candied nuts. Place a piece of baking parchment on a tray and put to one side. Add the sugar to a small, heavy bottomed pan, ensuring it's in an even layer and heat slowly. The sugar will slowly start to melt at the edges first. Continue to heat until the caramel on the outside is molten and golden brown with a couple of bubbles starting to appear. Do not stir! This should take about 4 - 5 minutes. Turn off the heat before the sugar goes too brown, as it will burn very quickly. There may still be a tiny bit of unmelted sugar in the middle. This is ok, just leave the pan for about 30 seconds to allow the remaining bit of sugar to melt.
Working quickly, add your nuts and stir with a wooden spoon, tip it out onto the baking parchment and then flatten the mixture out very quickly using the wooden spoon. Don't touch the mixture as it will still be very hot. Allow the nutty caramel to cool and harden ( about 5 - 10 minutes), then break it up using your hands.
Now you're ready to assemble. Use a palette knife to spread the frosting all over the top of the cake. Sprinkle the candied nuts on top and serve.
The banana bread without any toppings will keep well for 3 days if wrapped and placed in a sealed container at room temperature. With the toppings, the cake will last for around a day and a half before the candied nuts will start to soften. Keep covered and sealed in a cool room (there is cream in the frosting, so you don't want to leave it to get warm)..Nutritional Information is per serving.