Au Gratin Potatoes with Black Olives

Why I Love This Recipe
This is soothing and not too heavy. The original recipe, copied by my mom from a mystery novel, calls for light cream and dried herbs. I substituted whole milk and fresh herbs. Teenage picky-eater son ate two large helpings. That's a successful dish at our house.
Ingredients You'll Need
1 can pitted black olives, drained and halved
2 c light cream or whole milk
1 c onion, finely diced
1 1/2 tsp dried thyme or scant Tbsp fresh, minced
1 1/2 tsp dried basil or 1 Tbsp fresh, minced
1/2 tsp salt
1/8 tsp white pepper
3/4 grated parmesan cheese, divided
4 lg potatoes (about 2 lbs), peeled and sliced paper thin
4 oz shredded Gruyere cheese
Directions
Preheat oven to 375°.
In large sauce pan, mix together cream/milk, onions, herbs, salt and pepper.
Bring to a boil.
Lower heat and simmer 3 min.
Whisk in 1/2 c parmesan until smooth, about 1 min.
Add olives and simmer 3 min, stirring often.
Peel potatoes and slice them paper thin, I mean, paper thin.
Add to pot and stir gently until potatoes are covered in sauce.
With slotted spoon, transfer potatoes to greased 9 1/2" X 9 1/2" casserole.
Distribute remaining sauce evenly over potatoes.
Sprinkled gruyere cheese over top with remaining 1/4 c parmesan.
Cover dish and bake 50 min.
Uncover and bake 25-30 min longer until brown and bubbly.