I made these muffins from the Alison Holst book, 'More Marvellous Muffins', although I have a reprint, slightly different, edition.
You cut peach slices into some butter and sugar in the bottom of the tin, and add the batter on top.
Just a basic egg/milk/butter/sugar/flour batter, but it had a teaspoon of mixed spice in it which gave them a nice subtle flavour.
Once cooked you turn them out. I had to scoot a few bits of peach back into the right spot. They looked lovely piled on a plate to take out to spinning group.