Upside-down greengage cake

Today we were invited to a barbecue at some friends' house and as we're getting swamped with juicy sweet greengages from the tree in our garden, I thought I'd make some sort of cake and take along. The following is for a 13'' tin (just over 33 cm).

Ingredients

butter for the tin
18 greengages
170 g butter
170 g caster sugar
3 large eggs
340 g plain flour
5 tsp baking powder
1 dl apple juice

Method

1. Butter the tin, then line with grease-proof paper, then butter the paper.
2. Preheat the oven at gas mark 4 (180 degrees C).
   
3. Wash the greengages, cut in half and remove the stone, then lay them out at the bottom of the tin.
4. Melt the butter on low heat. Lightly whisk the eggs in a bowl. Mix the flour and baking powder in another bowl.
5. Whisk the butter and sugar light and fluffy.
6. Slowly add the eggs, while still whisking.
7. Add the flour a little at a time. When it feels like it's a bit too thick, add the apple juice.
8. Pour the mixture over the greengages and level it. Give the tin a tap, to make sure the cake mixture covers the greengages well.
   
9. Bake the cake in the middle of the oven for about 50 minutes. The cake is ready when you push a skewer through the middle and it comes out clean.

I made this yesterday and left it to cool down overnight. This morning I turned it out of the tin, the greengages were indeed juicy and had been dripping. I should have turned out the cake earlier to allow this juice to sink back into the cake. It worked mostly and the cake was quite nice. Served it with Waitrose's fresh vanilla custard.

One thing I forgot to mention is that this is the first time ever I sifted the flour as it's been in the packet for a while. I have vague memories of my Mum sifting flour for all her baking in the old days, haven't seen her do that in the last 25 years though. Still, it was interesting to try, visually the sifted flour had a lighter colour and definitely increased in volume a bit. Hopefully it also improved the taste of the cake too.