When I was on holidays in New Zealand, quite some time ago, I saw some beautiful brooches by artist Tamsin Cooper. She had hand-stitched seed beads into patterns on some, french knots onto others and embroidered others. They were so fine and delicate. I had a peek into how she made the backing brooches to see how the basic brooch block was made...
Firstly, cut 2 circles out of cardboard, one slightly larger than the other. Then cut a circle the size of the larger circle from fusible pellon. Next, cut circles from fabric, 1 1/2 times bigger than each of the cardboard circles.
Run a small gathering stitch around the outside of each fabric circle, leaving a tail.
Lay the pellon circle over the larger cardboard circle and then cover with the large fabric circle. Draw the thread up and gather the edges in. Cover the small cardboard circle in the same way, having first sewn a brooch back to the middle of the fabric circle.
Using small stitches, sew the small fabric-covered circle to the larger one.