Line a deep 7” Spring Form baking tin with a collar of oven proof paper, you need to go about 1” above the height of the tin.
To make the cake
In a mixing bowl combine the half pack of Madeira cake mix, 100ml water and 30ml oil and mix to form a smooth batter. Place the mixture in the baking tin – you can use the remaining mix to make muffins another time. Bake in the oven for 15 – 20 mins until cooked. Remove from the heat and leave to cool in the tin. Do not release the spring form.
To make the mousse
Separate out 6-7 strawberries to slice for the topping and place the rest into a food processor together with the condensed milk. Pulse until both are combined and fairly smooth (it doesn’t matter if you have small bits of strawberry in the mouse.
Put 60ml of hot water in a cup, add the cube of Jelly and fully dissolve (this adds a strong strawberry flavour to the mousse and helps it set) then add the Gelatin and stir until fully dissolved.
Put the cream and sugar in a mixer and whisk until soft peaks form, then fold in the strawberry and condensed milk gently then with the whisk on low slowly add the gelatin and combine fully. Pour the mix into the cake tin almost to the top, level the top and put in the fridge to set (at least an hour) – any remaining mousse can be put into dishes and set in the fridge as well to have later.
Dissolve the remaining jelly in the boiling water then add the cold water and leave to cool. Slice up the strawberries and lay them on top of the mousse. Press them down slightly to stop them floating when you add the jelly. Return cake to the fridge. Once the jelly has cooled pour it slowly on top of the mousse up to the level of the baking tin and leave in the fridge to set fully. You can leave it overnight in the fridge and eat the next day.
Before serving release the Spring Form and slowly remove the grease proof collar.