Preheat your oven to 180°C (160°C fan/350°F/Gas Mark 4). Grease and line a 20cm (8-inch) square cake tin with baking parchment.
In a large bowl, cream together the softened baking spread or butter and caster sugar until light and fluffy. This can be done with a hand mixer or a stand mixer.
Gradually beat in the eggs, a little at a time, ensuring each addition is fully incorporated before adding the next. If the mixture starts to curdle, add a tablespoon of the flour.
Stir in the vanilla extract.
Sift the self-raising flour into the bowl and gently fold it into the wet ingredients until just combined. Be careful not to overmix.
Pour the batter into the prepared cake tin and spread it evenly.
Bake for 30-35 minutes, or until a skewer inserted into the centre comes out clean.
Allow the cake to cool in the tin for 10 minutes before turning it out onto a wire rack to cool completely.
Once cooled, spread the raspberry jam evenly over the top of the sponge.
Sprinkle the desiccated coconut over the jam, ensuring it's well covered.
Slice and serve.
