A fabulous, comfort food, weekday dinner. Dress it up with a side salad and garlic bread, or eat it just as it is.
Two thirds fill a large saucepan with water and put on to boil over a high heat.
Heat the olive oil in a large, deep frying pan over a high heat and add the onion, garlic, celery and pepper. Make sure to stir the contents regularly so as not to allow them to brown, but cook until the onion is transparent and the celery & pepper have softened.
Add the black pepper and stir through.
Add the sliced chicken and continue to cook, stirring regularly, until the chicken has all turned from pink to white.
Reduce the heat to moderate and add the dried tarragon and stir through.
Once the water comes to a boil, add the pasta and cook until al dente. You don't want it to be cooked all the way through, as it will finish cooking in the oven.
Add the soup, milk, cream cheese and stock powder and gently stir until all is amalgamated. Allow the combination to come to a gentle simmer. Taste for seasoning and adjust if necessary, but remember that there will be cheese on top - so go easy on the salt! Add the frozen petit pois and stir to combine.
When the pasta is done, drain and make sure to retain a little of the pasta water, just in case you need to reduce the thickness of the sauce a little.
Replace the pasta back into the hot saucepan and add the sauce contents.
Decant into an ovenproof dish and lay the mozzarella slices over the top.
Cover with the grated cheddar and put into a pre-heated oven at 180degC/350degF/Gas4 for 20-25 minutes or until the cheese is melted, bubbly and just beginning to turn golden.