Preheat sheetpan & Boil water: Adjust oven rack to lowest position. Place large rimmed baking sheet pan on the bottom rack, unlined, and heat oven to 450F. Bring a large pot of water (about 2 liters) to boil.
Part-boil potato rounds: Add ½ tsp baking soda and potato slices to the boiling water. Stir, cover, and return to boil (about 7-8 mins), lower the heat to simmer, and cook for 1 minute or until the center of the potato offers resistance when poked with a paring knife. Set the potatoes aside to drain well.
Make herb infused oil: In the meantime, slightly warm up olive oil, ghee, or duck fat in a saucepan with rosemary and thyme. Season with a small pinch of salt, stir constantly so that the herbs won’t get burnt, about 30 seconds.
Toss & rough up the potato rounds: While the potatoes and the oil are still hot, in a large heatproof bowl, toss boiled potatoes with 2 tbsp rosemary & thyme infused oil and ½ tsp coarse salt, use a rubber spatula to vigorously toss and combine. The salt and oil in combination with the toss will create rough potato surface thus they turn crispy in the oven. Repeat the step with 2 more tbsp infused oil and ½ tsp coarse salt. Toss and combine until the exterior of the potatoes are coated with starchy paste (about 1-2 minutes).
Bake: Use an oven mitts to carefully take the hot sheet pan out of the oven. Grease the sheet pan with the remainder of the infused oil. Spread the potatoes evenly over with some gap between each slice and try not to overlap. Bake for 15 to 20 minutes, rotate the sheet pan after 10 minutes.
Bake flip side: Remove sheet pan from oven and use a metal spatula to loosen and flip the potatoes. Continue to roast until the flip side (second side) is golden crispy, about 10 to 20 minutes.
Garnish: Season with salt and pepper to taste and garnish with chive. Serve hot and immediately.
The crispy potatoes taste great without any dipping sauce but feel free to dip them in any sauce you like!To make ahead - complete the entire cooking steps. Let cool and pack the potato slices in freezer friendly bags or containers. To reheat - bake at 450F (or 425F for convection oven), middle rack for about 10 minutes total, flip after 5 minutes to reheat the second side.