Combine the softened butter, garlic, chives and parsley in a bowl. Season with salt and pepper. Mix until well blended. Transfer to plastic wrap and then roll up into a log. Stick in the fridge to chill.
Meanwhile, sprinkle the rib-eyes generously with salt and pepper. Mix the garlic powder, brown sugar, smoked paprika, chili powder and some salt and pepper in a small bowl. Rub the steaks with the spice mixture.
Grill the steaks over high heat on a well-oiled grill or grill pan, about 10 minutes per side for medium-well.
Remove the steaks to a cutting board and let rest for 5 minutes. Meanwhile, slice the garlic-herb butter into coins. Top each steak with a coin of the butter, and serve.