Preheat your oven to 180°c (160°c for fan-assisted ovens, Gas Mark 4 or 350°F) and a line 20x30cm (12x9-inch) baking tin with greaseproof paper. Set aside.
In a large bowl, cream together the margarine and sugar until light and fluffy.
Add the eggs one at a time, ensuring each is mixed through before adding the next. If the mxiture appears to curdle, simply add a spoonful of your flour to bring it back togther,.
Sift in the flour and gently fold to create a batter.
Transfer the batter to your pre-lined tin and bake in your preheated oven for 30-40 minutes until risen, golden and a skewer inserted comes out clean.
Leave to cool in the tin for a short while before transferring to a wire rack to cool completely.
Once your cake has cooled completely; warm your jam for about 20 seconds in a microwave (this isn't essential but it does make it easier to spread). Spread your jam over the top of your cake, being careful to get right into the corners and edges. Sprinkle your coconut over the top of your jam to finish.
