Start by lining an 8x8-inch baking tin with parchment paper, leaving a little overhang along the edges. This will make lifting the cake out much easier later. Preheat your oven to 170°C (150°C fan) / 340°F.

In a large mixing bowl, beat the softened butter or margarine together with the caster sugar until the mixture becomes pale, light, and beautifully fluffy.

Add the eggs individually, mixing thoroughly after each one. Stir in the freshly grated lemon zest, then gently fold in the self-raising flour until everything is just combined. Avoid overmixing to keep the cake soft and tender.

Transfer the cake batter into your prepared tin and spread it evenly into the corners using a spatula. Gently scatter the fresh raspberries across the surface, distributing them as evenly as possible.

Place the tin in the preheated oven and bake for 25–30 minutes. To check if it is ready, insert a toothpick into the centre. It should come out with a few soft crumbs attached, but no wet batter.

While the cake is baking, combine the icing sugar and lemon juice in a small bowl or jug. Stir well until the sugar has completely dissolved and you have a smooth syrup.

As soon as the cake comes out of the oven, prick the surface all over with a toothpick or skewer. Slowly pour the lemon syrup across the warm cake, allowing it to seep into the little holes and add plenty of moisture and citrus flavour.

While the cake is still warm, carefully cover it with cling film to help retain its moisture. Leave it undisturbed until it has cooled completely before moving on to the glaze.

Place the icing sugar, lemon juice, and milk in a bowl. Whisk everything together until you have a smooth, pourable glaze without any lumps.

Meanwhile, gently heat the raspberry jam in the microwave or in a small saucepan until it becomes warm, loose, and easy to drizzle.

Once the cake has cooled completely, turn it upside down onto a cooling rack so the flat bottom becomes the top. Pour the lemon glaze evenly over the surface, spreading it gently with a spatula.

Spoon or drizzle the melted raspberry jam over the lemon glaze. Using a toothpick, skewer, or the tip of a knife, gently swirl the jam through the icing to create a lovely marbled finish.

Leave the cake at room temperature until the glaze has set nicely. Once firm, cut into squares and serve.