Heat the oil and butter over medium-high heat in a large 12” skillet (preferably cast iron).
Add in the sprouts in an even layer, cut side down.
Cook, undisturbed for 3-4 minutes until browned and crisp.
While they cook mix together the honey, lemon juice and sriracha in a small bowl. Set aside.
Flip the sprouts and let cook for another 2 minutes.
Add the cashews and a good pinch of salt and cook 2 minutes more.
When the sprouts look well browned remove from the heat and add the sauce. Mix well so the sprouts are all coated. Give them a sprinkle of flaky salt and serve immediately.