In a saute pan over medium high heat, add the olive oil. Then add the diced pancetta and let cook. Stir occasionally, turning the chunks so they get crispy on all sides. This will take about 10 minutes.
Once the pancetta is starting to get caramelized and crispy, add the onions, a bit of salt and toss to combine. Let the onions cook about 5 minutes, stirring well.
With the crispy pancetta and softened onions, next add 2-3 tablespoons of water to deglaze the pan, stirring well to lift up all of the crispy bits on the bottom. Now add the thinly sliced cabbage, another few pinches of salt and stir to coat.
The water in the bottom of the pan will help wilt the cabbage but will evaporate before the cabbage is cooked. If needed, add a little more water or oil in the pan. Continue to stir the cabbage so that it all melds nicely and cooks evenly.
Saute the cabbage until it's wilted to your liking. Add freshly ground black pepper and stir to combine. Taste the cabbage and adjust the seasoning if needed.