Preheat oven to 350 degrees.

grease 9x13 baking dish with 2" high sides.

Stir cream and Boursin in heavy saucepan over low-medium heat until cheese melts and mixture is smooth.

stir chopped rosemary into cheese sauce

pre-cook potatoes in microwave for 4 minutes. (pierce potatoes before cooking...usually 2-4 minutes in the microwave, turning once, is all they need) this will allow the potatoes to cook more quickly.

slice potatoes into thin slices.

layer potatoes and pour 1/2 cheese mixture over potatoes, salt & pepper

repeat with one more layer.

Bake until top is golden and potatoes are tender. Usually 45-60 minutes or until the potatoes are fork-tender (you might have to adjust the temperature if browning too quickly).