NPH insulin has the advantage that it can be mixed with an insulin that has a faster onset to complement its longer lasting action, which is the primary reason NPH remains on the market today, because manufacturers sell a variety of premixed insulin formulations.
Wrap the foil tightly around the brisket to seal in heat and moisture while it cooks. Place the baking dish with the aluminum-wrapped brisket in the oven and bake for around one hour per pound of meat. Increase cooking time to 90 minutes per pound if you are cooking larger cuts of brisket, those weighing 8 to 12 pounds.
Bake the brisket in a preheated oven at 300 F for 4 to 6 hours, turning it every 90 minutes so each side is immersed in the cooking liquid approximately half of the time. It's done when you can easily slide a fork or the tip of a paring knife into the meat.