In a small saucepan, combine strawberries, sugar, cornstarch, water, and lemon juice.

Cook over medium heat, stirring frequently, until the mixture thickens and takes on a glossy appearance (5–10 minutes).

For a smoother texture, mash the strawberries as they cook.

Allow the filling to cool completely before using.

Preheat your oven to 180°C / 160°C (fan) / Gas Mark 4 / 350°F.

Grease and line two 8-inch round cake tins.

In a large mixing bowl, cream together the butter, sugar, and vegetable oil until pale and fluffy.

In a separate bowl, whisk the eggs, milk, and vanilla extract until combined.

Gradually add half the wet mixture to the creamed butter, mixing until smooth.

Sift in half the flour and gently fold it into the batter. Repeat with the remaining wet and dry ingredients.

Finally, fold in the baking powder until just combined.

Divide the batter evenly between the prepared tins and bake for 25–30 minutes, or until a skewer inserted into the center comes out clean.

Let the cakes cool in their tins for 20 minutes before transferring them to a wire rack.

Beat the softened butter until pale and fluffy.

Gradually sift in the powdered sugar, beating well after each addition.

Mix in the vanilla extract, 4–5 tablespoons of strawberry filling, and a pinch of salt. Beat until smooth and creamy.

Place one cake layer on a serving plate or cake board.

Pipe a ring of buttercream around the edge to create a "wall" and spread the remaining strawberry filling inside the ring.

Add the second cake layer on top and cover the entire cake with buttercream, smoothing it with a spatula.

Decorate with fresh strawberries for a stunning finish.