I combined palestrina and back stitch in one of my Jacobean Leaves designs, and liked the effect so much that I've used it again here. But I learnt a trick or two this time round.
Stitch the palestrina first, keeping inside the outline of the wing. Then do back stitch along the line. I did it as a stab stitch – each back stitch in two moves, up then down, rather than one – which made it easier to get a neat and evenly spaced line of back stitch alongside the row of palestrina. And use a lighter shade of the same colour for the back stitch to get the same effect using a different colour.
Download the pattern for Flutter By 2 from the free patterns section on my website. And go to the useful links page for stitch books and online stitch libraries.