I will tell you what I tell everyone. You just have to make them. Not much of a recipe but a hell of a dish. The carrots turn golden brown, sweet and delicious. You would think there was a sweetener of some sort added. Carrots and onions have the most natural sugar of all the vegetables, that is why they are in every soffritto. Cook them together and....now you understand. —Stockout
Peel and slice carrots, diagonally in 1/4" slices (see pic).
In a dutch oven or even a cast iron pan with a lid, add butter, carrots and onions. When the butter has melted, stir to coat each carrot slice and break up the onions. On low heat, cook, covered for 15 minutes.
After 15 minutes, almost all of the water that comes out of the carrots and onions will have evaporated. This is when the caramelization starts to take place. Stir every 7-8 minutes. It should take 50 minutes from start to finish.
When a good amount of the carrots and onions are caramelized, shut off the heat and cool. Store in the refrigerator overnight or up to 3 days. If you need to freeze them, they defrost perfectly. Can be nuked to reheat.