In a large skillet, melt the butter.
Season the chicken and cook at medium high heat until browned and done. (About 3-4 minutes per side - needs to be 165F in the middle). Remove to a plate and keep warm.
In the same skillet, cook the onions until softened (I deglaze the pan with a little stock as well), then add the garlic and roasted red peppers.
Cook for 2 minutes then add the Arla cream cheese and the remaining stock.
Whisk the sauce until blended, then simmer for around 7 minutes – allowing the sauce to reduce.
Add the spinach and toss into the sauce until wilted.
Add the chicken and any juices back into the pan and allow to warm through.
Plate the pasta, add chicken and spoon a good helping of the sauce over the top.