Heat oven to 180C/fan 160C/gas 4. Butter and line the base and sides of a 20cm round cake tin. Peel, core and slice the apples to about the thickness of a £1 coin. Melt the knob of butter in a large frying pan then tip in the apples. Cook over a medium heat, stirring every so often till softened, but not soggy, about 5 mins. Splash in the Pomona and leave to cool. Tip onto a plate to cool more quickly if you like.
Using an electric whisk or wooden spoon, beat the softened butter and sugar until creamy and light. Add the eggs a little at a time, beating after each addition, then fold in the flour and almonds. Finally, fold in half of the cooled apples. Spoon the mix into the prepared tin, smooth the top and scatter with the rest of the apples, pressing down lightly into the batter.
Bake for 1 hr, until golden and a skewer inserted into the middle of the cake comes out clean. Check the cake after 45 mins, cover with foil if it’s browning too quickly. To make the glaze, warm the jam and Pomona in a small pan until the jam melts.
Once the cake is out of the oven, prick it all over with a skewer and drizzle over a little more Pomona. Cool for 10 mins, then turn out of the tin and transfer to a wire rack. Brush the glaze over the apples and serve sliced, with dollops of Pomona cream. Best eaten on the day it’s made, or warmed through the next.