Set up a large container and fill three quarters of the way with warm water.
Anchor the immersion circulator onto the side of the container and set the desired temperature.
Seal unseasoned ribeye steaks into individual bags and place in preheated water for a minimum of 1 hour and a maximum of 3 hours. (My preference is 1.5 inch steaks at 130° for around 2 hours. I like a medium-rare steak that still has a good bite.)
Place steaks in the sous vide bath for 1-3 hours. (For meat cooked under 130°, it can not be left in the cooker for more that 2 ½ hours. )
Remove the ribeye steaks from the plastic bags, pat dry, and let them rest for 10 minutes.
Season the meat generously with salt and pepper. I like coarse salts like sea or kosher and cracked pepper.
Heat up a cast cast iron pan on medium/high heat. When the pan is just at its smoke point, drizzle a small amount of canola oil in the pan. Lay the seasoned steak down in the pan along with rosemary stems and two cloves of garlic
Let the high heat brown the meat. After 1-2 minutes, turn the steak and brown the other side. Add butter to the pan, and spoon the melted butter over the steak.