Painting with egg tempera over gold leaf
I've worked with gold leaf before, but I've only ever applied it after painting. With the work that I'm currently planning, I'd like to cover the panel in leaf and paint my subject in the centre of the panel, over the leaf, so that it is not only surrounded by gold, but that the gold comes through. I'll be working in egg tempera and I only use real gold leaf, not imitation gold (i.e. copper) leaf, and because gold leaf is expensive I don't want to ruin it. My worry is that I've always been taught that tempera needs gesso directly under it, to hold onto, but if I gesso over the gold in the outline of what I'll be painting, it will cover the gold and keep it from coming through, which defeats the purpose of painting over the gold.
What shall I do?