Peel the Potato, Turn the oven to 425°F
Preferably using a mandolin, slice the Potato between an 1/8" and 1/16" thick… If you don't plan on getting the tape measure out, not so thin you can see through it but not so thick you can't easily layer the slices.
Place the pan over low heat on the cooktop and melt 1/4 cup of Butter. As soon as Butter is melted turn heat off and remove from the heat.
Let the Butter cool slightly so you don't burn yourself. Start in the centre with a single slice of Potato. Over lapping each slice work your way to the edge of the pan.
After you have created one layer sprinkle Salt and Pepper and any Herbs or Seasonings over the top, ladle or spoon Butter over the top.
Repeat with another layer of Potato slices, starting in the middle and working your way out in the opposite direction from the previous layer.
Top again with Salt, Pepper, any Herbs or Spices you're using and more Butter to coat. ( I used puréed Garlic and Rosemary inside mine ).
Continue to do this until all the Potato is used up. Depending upon the size of your pan this may lead to the Potatoes higher than the top of the pan but they will shrink as they cook.
Make sure to only Salt and Pepper the top, no Herbs or Spice, and use up the rest of the Butter.
Place the pan back on the cooktop on medium heat and heat up until the Butter is bubbling around the edges.
Give the pan a good wiggle to make sure the Potatoes haven't stuck to the bottom of the pan.
Cover the Potatoes with aluminum or lid, and place in oven for 40 minutes. After 40 minutes remove the Foil and cook for another 10 minutes.
Remove from the oven and set aside to cool for 10 - 15 minutes.
There is a lot of Butter so will have to remove the excess. I found holding the potatoes in place by lightly pressing down on them with a large metal spatula worked best.
Start by gently tilting the pan to one side and letting the butter flow down. Still pressing with the spatula lift and pour the Butter into a reserve bowl.
Next is removing the Anna Potatoes from the pan. Start by wiggling the pan again to make sure the Potatoes are loose.
Preferably using a serving platter larger then the pan ( use the back of a sheet pan if there is nothing else available ) place it top side down over the pan. Holding the platter with one hand, in one motion flip the pan and platter so the platter is on the bottom now.
Gently lift the pan off the platter to reveal beautiful Anna Potatoes. Grab a knife, slice it like a pie and...Enjoy!