Yes, caramelized onions should be naturally gluten free. However, so few people take the time to make this wonderful ingredient. There is a world of difference between a raw onion (crunchy, pungent, peppery flavor and watering eyes) and caramelized onions (soft, sweet, buttery, rich and slightly nutty). Caramelized onions are quite easy to make - they just require three ingredients, time and a little patience. We are not talking about quick, high heat browning of onions (think fajitas) where the outside is charred and the inside still has that pungent punch. We are looking for a tender onion with a sweet flavor. This recipe presumes a little cooking know-how on your part, but just dive in.
Melt butter in a large sauté pan over medium-low heat.
Add the onions to the pan - it is ok if they are in a large mound and barely fit. Sprinkle the salt over the onions. In addition to adding flavor, the salt will draw water out of the onion making them tender and ripe for caramelization.
Cover and cook the onions. Resist the urge to turn up the heat and make this go faster. You are sweating the onions. This process allows all the water from the onions to release into the pan and then evaporate slowly. It ensures that your onions will be soft and caramelized all the way through and not just on the outside. Once the onions are sitting in a pool of their own water, remove the lid and continue to cook. Stir occasionally until the onions are soft and anywhere from honey-colored to deep brown. This process can take up to an hour depending on how many onions you are cooking and your preferred level of caramelization. Don’t worry; as long as you cook them slowly and stir them frequently, you will not end up with burned onions.
So what crazy kitchen alchemy is taking place?
Onions are made up mostly of fiber and sugar which means browning will occur through caramelization. There are many who wax poetic about the differences and qualities of the maillard reaction and caramelizaion (important information for sure). However, as recreational cooks, it is important to understand is that a brown color and a more complex flavor are generally the end result of these processes. Cooks use them to produce beautifully browned, deeply flavored foods. And for those who know me, they know my mantra is "Color equals flavor!"