Heat oven to 500 degrees F.
[This is really, crazy hot. If you’re really nervous, I suppose that 450 degrees or 475 will also work, but I made it both times at 500 without problems.]
Place melted butter in the bottom of a large bowl. Stir in herbs, if using, salt, and pepper. Add potato slices and mix to evenly coat them. Spread potato slices and all of the good stuff at the bottom of the bowl in a 9×13 (quarter-sheet) metal (a glass baking dish shouldn’t be used at this high of a temperature) baking pan.
Roast potatoes for 15 minutes. Use a thin spatula to loosen potatoes and turn them over. Roast for a second 15 minutes, then carefully pour stock or broth into pan and add the garlic cloves. Roast for 15 minutes more, until potatoes are fully tender.
Remove from oven. Transfer to a serving platter along with any remaining liquid in pan and serve warm to very lucky people.