To make the streusel topping put the flour, sugar, and cinnamon in a bowl and mix them.

Add the butter and rub it with your fingertips until you get a crumbly dough.

Wrap the dough in cling film and stick it in the fridge for 30 minutes.

While the dough is chilling, preheat your oven to 190C. Grease and line your baking tin.

Beat the butter and sugar in a bowl until it turns pale and creamy.

Mix in the lemon zest.

Gradually add the eggs, mixing well each time to prevent curdling.

Sift flour into the mix and fold it in gently using a metal spoon.

Add the milk and mix gently.

Spread half the cake mix into your tin and smooth it out.

Lay half the apple slices on top.

Spread the rest of the mix over the apples and smooth it again.

Arrange the remaining apple slices on top.

Get the streusel dough out of the fridge and grate it.

Sprinkle the grated streusel evenly over the top of the cake.

Bake the cake in the centre of the oven for 45 minutes. Use a skewer to check if it's done – if it comes out clean, your cake's ready. If not, bake it a bit longer.

Let the cake sit for 10 minutes before you remove it from the tin.

Cut into slices and enjoy as it is or with some ice cream or custard.