Peel the shallots and brown them in a skillet over medium / high heat with the butter, once it is bubbly, and a pinch of salt. About 10-15 minutes to caramelize slightly.
Then we incorporate the sugar and brown for a couple more minutes.
Next, pour in the drizzle of balsamic vinegar and the dark background, which should almost completely cover the shallots, and cook over medium heat 20 minutes, keeping the boil.
After 20 minutes, the onions will be very tender and the sauce will have thickened.
We serve the balsamic shallots hot with meats.
recipe by Kitchen Recipes at https://www.lasrecetascocina.com/chalotas-balsamicas/