Losie, love your colors. A pretty block.
Mousie,I don't know which method you are using, but I am doing invisible machine applique, and I pretty much cut the "frame" fabric as a whole piece, appliquéd that, then cut background brown fabric from behind it leaving a little seam allowance, turned that piece under( only messed up on cutting so I had to fiddle with it a bit), appliquéd it in top and wallah. I think that is the way Pat and Kathy(originally) did it or that I how I understood they did it and did mine,lol. Clear as mud?