Carefully slice pancetta into 1/2 to 1-inch squares. (No need to be super-exact here - the pieces will cook to different sizes depending on their fat content. Just make them big enough to see and enjoy in one bite. See my photo above.)

Set colander in large bowl.

Place a large Dutch oven over medium-low heat.

Add olive oil and allow to heat just a bit.

Add cut pancetta pieces to Dutch oven and cook, stirring frequently, for about 8 to 10 minutes, until the fat is rendered and pancetta is deep golden brown but still has slight pinkish hue. Adjust the heat if the pancetta is cooking too fast.

While pancetta cooks,

Place a large pot with 2 quarts water on the stove over high heat and bring to a boil. Do not add salt.

When boiling, add pasta and cook, stirring often, until just al dente. Drain pasta in prepared colander, reserving cooking water.

When pancetta is cooked, remove Dutch oven from heat and use a slotted spoon to transfer the pieces to a small bowl. Set aside.

Very carefully pour grease from pot into heat-proof (glass or metal) liquid measuring cup until you have 1/3 cup. Discard the remaining grease.

Return the 1/3 cup grease to the Dutch oven and place back over heat.

Add pepper and 2 cups reserved cooking water (from the bowl under the colander) to Dutch oven with fat.

Bring mixture to a boil over high heat.

Boil mixture rapidly. Be sure to scrape up any browned bits left over from cooking the pancetta. Boil about 5 - 7 minutes until mixture is reduced to 1½ cups. (I used the same measuring cup as before to get this exactly right. I had to pour it back in once to reduce a bit more.)

When mixture is reduced, lower heat to low.

Add pasta and pancetta. Stir well to evenly coat.

Add Pecorino cheese, a little at a time, and stir each addition until cheese is melted. Continue until all cheese is used and sauce is slightly thickened, about 1 minute.

Remove from heat and check sauce consistency. Adjust if you need to with a small bit of the remaining reserved cooking water. Transfer pasta to serving plates, sprinkle with a small amount of remaining Pecorino and dust with freshly ground black pepper (something I forgot to do before I took the picture).

Serve immediately.