Thin out the chicken by placing them between two pieces of baking paper and using a rolling pin to gently press them down at the fat end. Season with salt *See notes
In your pan heat about 2 tablespoons of oil. Gently fry the chicken until each side is golden and mostly cooked through. This will take about 4 minutes per side depending on how thin you've pounded the chicken. Once the chicken is cooked, place them on a plate and set aside. Add the pancetta to the pan and fry until crispy. This should only take about 3 minutes. Set the pancetta aside with the chicken breast.
You can leave the bacon fat in the pan to cook the onion or drain some of it off. Personally, I leave it all in. Gently fry the onions and garlic until they are golden. You may need to add a splash of water to the pan to scrape up any golden bits from the bottom of the pan from cooking the chicken and bacon.
Once your onions are soft and golden, you can add in the pasta shells.
Add in the chicken broth (made with a stock cube!) and bring to a boil. Turn the heat down to a simmer and cover for about 10 minutes, until the pasta is mostly cooked. You don't want the pasta fully cooked at this stage, as we're adding in the cream and continuing to cook for a further few minutes. *See Notes
When your pasta is 90% cooked add in the double cream and parmesan cheese and bring to a gentle simmer for about 3 minutes until the sauce is thickened slightly. Add the parsley and bacon to the pan and stir well. Slice the chicken and place on top to serve. Sprinkle with some fresh pepper and place the pan in the middle of the table to serve.