Preheat oven 375°F

Brush 13x9 glass dish with 2 tbsp oil

Slice potatoes lengthwise 1/8th thick

Slice garlic thinly.

Slice mushrooms

Arrange 1/3rd of potatoes slightly overlapping in a dish. sprinkle with coarse salt and pepper.

Pour 1/3 cup of cream over.

Sprinkle with 1/4 cup of cheese

Repeat layering 2 more times

Bake uncovered until potatoes are tender, adding cream if dry. about 45 min

Sprinkle thyme and garlic slices over gratin.

Toss mushrooms with 3 tbsp of oil. Sprinkle with salt and pepper

Arrange mushrooms slices atop of gratin around edge of dish

Drizzle with 1/4 cup cream, sprinkle with/4 cup cheese

Continue to bake uncovered until mushrooms are tender and potato edges are golden brown about 20 minutes

Can be made ahead one day

Cool hour in dish and chill

cut into 10 pieces And transfer to dish.

Cover with foil and real in 350°F oven 10 to 15 minus