This is an original from The Old Spaghetti Factory and has long been a favorite of mine. In fact, when I go there it's the only thing I order. I've been making it myself for at least twenty years now. Sometimes you have to shop around for the cheese, but it is well worth it--yum!
Cut the butter into tablespoon-sized pieces and place in a medium saucepan over medium heat. Bring the butter to a slow boil--about 5 minutes.
When the butter starts to boil, stir constantly to prevent residue from sticking to bottom of pan. As the butter cooks it will start to foam and rise. Continue stirring (about 5 more minutes). Otherwise the foam could overflow and catch fire.
When the butter stops foaming and rising, cook until amber in color (about 1 to 2 minutes). It will have a pleasant caramel aroma.
Turn off the heat and remove pan from burner. Let the sediment settle to the bottom of the pan for a few minutes. Pour the brown butter through a strainer into a small bowl. Do not disturb the residue at the bottom of the pan.
The brown butter can be stored in the refrigerator and reheated in the microwave as needed.
Boil the pasta according to package directions and divide into four servings. Spread 1/4 cup of mizithra over each pasta serving. Top with 1/4 cup of hot brown butter. Enjoy!
NOTE: Some people, myself included, actually like the residue from the bottom of the pan to spoon a bit over the pasta. But be careful: this makes it extra salty.
If mizithra is unavailable, a blend of ricotta salata and romano may be substituted.