Heat heavy skillet or pan on medium high heat.
Add 1/2 butter, let melt (but NOT brown)
Add chicken thighs, let brown to a deep golden brown on each side, flipping after about 3 minutes.
Remove chicken thighs from pan when browned on each side (not fully cooked through), set aside.
Add other 1/2 butter and garlic to pan.
Let garlic brown, about 3 minutes.
Add cilantro, blackening seasonings, stir and heat 1 minute.
Add stock, let boil and reduce slightly - about 2 minutes.
Add chicken back to pan and let cook rest of the way to 165 internal temp while sauce reduces, about 6-8 minutes, stirring occasionally to prevent burning.