Made mushroom, Swiss Cheese and carmalized onion burgers with a bit of mayo for lunch.

My girlfriend knows I love food and cooking so she bought some stuff for me from whole foods. And the components in these burgers are part of.
To start I carmalized 3 large yellow onions took about an hour and a half, then removed the onions from the pan added a little bit of butter sautéed some mushrooms, removed those from the pan the toasted the buns. Removed those, then cooked the burgers in the same pan. About two minutes before I pulled them out I added some of the onions and mushrooms to each topped each with two slices of Swiss Cheese then hit the pan with a splash of water and covered the pan to melt the cheese. Before I pulled them out I put a small slather of mayo on the bottom of each bun. Put the burgers on the bun and ate them both. Now I need a nap.