A classy appetizer that you can prepare with a little planning. Make the onion confit the night before and all you have to do is assemble each bite-sized tasty the next day. Try it at your next party! Use gluten-free bread if you are gluten intolerant. If you don't like onions, well, you're kind of out of luck, but I'd encourage you to try it anyway, because onions slow cooked are so sweet and delicious. Maybe, you'll be an onion convert!
Melt the butter in the slow cooker and coat the inside of the slow cooker with butter.
Add the sliced onions and thyme to the slow cooker and set overnight up to 24 hours on low heat. Be sure that the sliced onions are uniformly sliced so that the onions caramelize evenly. On the next day, you should have perfectly caramelized onions, ready for your crostini.
Toast the baguette slices until golden brown and crispy.
Assemble the crostini in the following manner - brush the baguette slices with with olive oil, top with onion confit, Gruyere cheese, and chive.
Transfer to a serving platter and serve at room temperature.