Pesto Potato Gratin

2 lb. russet potatoes
3 Tbsp. olive oil
1/3 cup pesto
1 medium onion, thinly sliced
250 g fontina or provolone cheese, grated
Salt and pepper

Peel and slice potatoes into 1/8" slices.
Spread 1 Tbsp. oil in bottom of a large, flat casserole dish. Place half of sliced potatoes in dish in an even layer.
Season with salt and pepper. Spread with pesto.
Spread onions over pesto in an even layer. Cover with remaining potatoes.
Season with salt and pepper, and drizzle with remaining oil.
Cover tightly with foil and bake at 350 degrees F for 1 1/2 hours.
When potatoes are tender, remove foil and sprinkle evenly with cheese. Bake for another 10 minutes until melted and bubbly.

Makes 6 servings