Heat the oil in a small skillet over medium heat. Add onion and stir every minute until soft and deeply golden brown about 10 minutes. Add the vinegar. Turn down heat one level.
Cook for about 3 minutes until the liquid thickens, or “reduces,” by about half.
Mix in ketchup, tamari and coconut sugar until they dissolve.
Then, mix in the smoked paprika and cayenne pepper.
Bring to a boil. Simmer for 5 minutes.
Remove from the heat.
On the Grill
Meanwhile, preheat a grill and lightly oil the grates.
Halve and pit the peaches. Run a sharp knife along each peach's seam to halve them. Remove the pit and brush each cut side with olive oil.
Place the peaches cut-side down on the grill and cook undisturbed until grill marks appear, 4 to 5 minutes.
Flip the peaches and cook until tender, 4 to 5 minutes, until the skins are charred and the peaches are soft.
Roll your thighs in your prepared onion sauce. You can use a large casserole pan, or a sheet of foil on a cookie sheet. (Fewer dishes!) Save the leftover sauce for drizzling.
Place thighs on the grill for approximately 5 minutes; flip chicken and allow it to cook for another 5 minutes.
Check the temp! Cook chicken until it reaches 165°F, you may need to cook another 4 to 5 minutes on each side and recheck.
To assemble your dinner: Add a base of leafy greens, add the chicken thighs and peaches to follow. We prefer the remnants of the onion sauce to dress it, but a balsamic vinegar works well too!
Notes
To substitute bone-in, skin-on chicken thighs, grill the chicken thighs for an additional 5 to 10 minutes over indirect heat until the internal temperature reaches 165℉. Finish the chicken skin-side down over direct heat to ensure crispy skin.