• Preheat oven to 375 degrees F.
• Peel potatoes and hold them in a bowl of water.

Make your Béchamel Cheese Sauce

• In a medium saucepan, melt butter over medium heat, then add garlic and cook for 30 seconds or until fragrant. Stir constantly so the garlic doesn't burn.
• Add in flour and continuously stirring cook for about 30 secs. 
• Whisk in milk and heavy cream gradually, keeping at a low simmer, about 1/2 cup at a time.  Slow down if you lose your simmer. 
• Add 1 tsp of sea salt and 1/4 tsp black pepper and hot sauce if you're adding it.
• Once sauce is thickened to about the consistency of heavy cream to buttermilk, turn burner down to low and whisk in your shredded gruyere cheese.
• Once fully melted, turn off burner and remove from heat.  Let sit while you start slicing and building the Au Gratin Potatoes.

Build your Au Gratin Dish

• Slice a few potatoes at a time or all if you can work fast and add them to your greased baking dish, in a "scalloped" fashion, overlapping about 1/3 of the way till you cover the bottom of the baking dish.
• Grind or sprinkle just a little salt and pepper to the potato layer.
• Spoon on a spread out about 1/3 of the béchamel sauce onto the potatoes
• Scatter about 1/3 of the shredded cheese atop the sauce and then make 2 more layers of potatoes, salt & pepper, sauce & cheese.
• Your top layer (the 3rd one will have the last of the scattered shredded cheese on top.
• Bake the Au Gratin for 1 hr at 375 F.  It should be nice and golden on top and bubbling.  You can test the tenderness with a sharp knife if you like before removing it from the oven.
• Let the potatoes sit for at least 10 minutes and then you can serve it by slicing it into squares.