How long to get the right blackened sear?
High heat is the answer - you want it crispy on the outside (but not burnt), and rare inside. On a BBQ make sure it is hot hot hot; on a stove top use a cast iron grill if you have or cast iron pan with grooves, again smokin' hot; or broil.Either way turn when browned nice and crispy, and second side does not take as long. Of course, thicker cuts are easier to do. Use a thermometer if unsure. A sprinkle of sugar helps crisp the steak as it will caramelize quickly with the high heat.
Do you weight it down with a brick to sear better?
If the heat is high enough you don't need a weight - that only pushes the flavorful juices out.
Pittsburgh rare refers to the days when the workers would take a slab of meat down to the steel factories--the pipelines were so hot that the workers would throw the meat on the pipes for their lunches. The trick is super hot cast iron. The way I learned (in Pittsburgh!) was to invert a cast iron skillet over a hot flame, leave the skillet for a minimum of 15 minutes (around here, the skillet is left all day with the flame on constantly), this iron surface is what you need to sear your steak, a minute or two each side. Super high heat with cast iron is all you need, no brick.
Excellent . Thanks