Apple and Ginger Shortcake Slices

I had a nice surprise at work the other day when the lovely Ady left a jar of 'Ginger Preserve' on my desk, hinting to a colleague that, should I want to make a sweet treat that he could share in, he wouldn't say no - so how could I say no?!  The ginger preserve is, effectively, chunks of preserved ginger set in lemony jam.  Very nice - so, I mixed several tablespoonfuls with a couple of grated eating apples and layered this with a shortcake mix I found online - US measures, I'm afraid.  A stick of butter (about 100g), melted.  I egg, beaten.  1/2 cup caster sugar, 1and 1/2 cups of plain flour with a teaspoon and a half of baking powder.  Mix these together, and press a little over half over the base of a parchment-lined 20cm square baking tin.  Spread the apple ginger mix over.  Now, mix the remaining shortcake mix with two tablespoons of chopped nuts.  Sprinkle this in clumps over the top, then bake at 170C (fan) for 30-35 minutes.  Allow to cool in the tin, then cut into 16 squares.  Yummy!  Hope you like it, Ady.  The rest of the jam will be mixed with rhubarb for a steamed pud on Sunday with custard.