3 Russet potatoes, peeled and sliced thin
3 cups whole milk
1 cup heavy cream
1 yellow onion, sliced thin
2 cups white sharp cheddar cheese
1/3 cup grated parm
1/2 tsp. fresh thyme, plus a few sprigs
Preheat the oven to 350.
In a large pan, combine the potatoes and the milk. Bring the liquid to a boil and then turn the heat down to low. Let the potatoes simmer 5-10 minutes so they can soften a bit. Add 1/2 tsp. of thyme and remove from heat.
In a small pan, sauté the onion in a bit of EVOO and then add the onions to the potatoes. Mix gently.
This is the part where you have to pay attention! Drain the liquid from the potatoes but be sure to KEEP THE LIQUID. You’ll use the starchy milk later. (You should have between 2-3 cups once the potatoes are drained.)
In a baking dish (9×13 or larger), make your base layer of potatoes. This should be about 1/2 of the total potatoes. Then pour in 1/2 cup of heavy cream. Add a healthy handful of sharp cheddar cheese. Then pour in 1 cup of the milk reserve. Sprinkle a little S&P on top.
Layer the rest of the potatoes on top of the mixture. Top with the final 1/2 cup of heavy cream. Add 1 more cup of the milk reserve. Sprinkle a little S&P on top. Finally, add 1/2 cup of cheddar cheese and the parm cheese. Top with a few sprigs of fresh thyme.
Bake 30-35 minutes or until bubbly and the cheese on top is golden brown.