In a large sauce pan over medium heat, melt the butter and olive oil. When the oil is hot, but not smoking, saute the chicken strips. It should only take a couple of minutes on each side. Do the chicken in batches so you don't crowd the pan. When chicken is cooked chop it into bite sized pieces and set aside.

Meanwhile, cook fettuccine as directed on package. I usually go for the lower cooking time to ensure the pasta doesn't get over cooked. Drain the pasta well.

I use the same pan for the chicken as for the sauce. If you have burned bits, wipe out the pan with a paper towel. If it's fine, just add it. Then, add cream and butter. Bring to a boil on high heat. Reduce heat to low and simmer for 2 minutes. Add about 1/3 cup of the Parmesan cheese and whisk until smooth. Add pepper to taste (about a teaspoon). Whisk in lemon juice and chicken stock, then add spinach and cook until spinach is wilted. I rarely add salt as the cheese has a lot of salt and the pasta is cooked in salted water but taste and adjust according to your own taste.

Add drained pasta to sauce and toss well. Then add remaining Parmesan Cheese and chicken. Give it another quick stir, then serve right away.