Sourdough

I use my over-the-stove microwave as a proofing enclosure.  I put the goods inside and turn on the light that illuminates the stovetop.  The light keeps the oven gently warm.  To get the inside nicely warm initially, I sometimes heat a container of water it to a boil  That could enable a countertop microwave, too.  It's a LOT easier than transporting a hot pan of water to a stove oven and holds a good temperature longer.