Preheat a Fan oven to 180 C ( 350 F, Gas 6) and grease the base of a 2lb loaf pan with butter. Line with baking parchment.
Put the apple chunks in a bowl and toss them in the lemon juice.
Sift the flour and the baking powder into a separate mixing bowl with a pinch of salt and the sugar. Gradually add the beaten eggs, whisking well all the time.
Add the melted butter, chopped rosemary and lemon zest and mix well to combine. Drain the apple slices and fold into the cake mix. Pour the mix into the prepared loaf tin and add the rosemary sprigs and flaked almonds on top.
Bake in the oven for 35 minutes until golden and well risen- a skewer inserted into the middle should come out clean. Remove from the oven and leave to cool in the tin for 10 minutes before turning out onto a wire rack to finish cooling.
While the cake is baking heat the apricot jam and the lemon juice over a low heat until melted down. When the cake is slightly cooled brush over the top. Serve when cool.