Set the oven and prep the potatoes. Preheat the oven to 400° F, adjust a rack to the center, and add the potatoes in an even layer to a sheet pan. Drizzle them with the 2 tablespoons of olive oil and sprinkle generously with salt and pepper. Move the pan around to be sure all of the potatoes are evenly coated.
Roast the potatoes. Once it's preheated, place the sheet pan in the oven and roast the potatoes until they’re tender when pierced with a fork, about 40 minutes. Jiggle the pan to move the potatoes around about halfway through the cooking time. The skins should be wrinkled and slightly golden when they're done.
While the potatoes are in the oven, cook the onions, garlic, ginger and peppers. Coat the bottom of a large sauté pan with olive oil and place it over medium heat. Add the onions and cook, stirring often, until they're soft and a bit golden, about 8 minutes. Add the garlic, ginger pulp and chili pepper to the onions. (The ginger is most easily grated into a pulp with a microplane zester.) Add sugar and spices. Cook for about 3 minutes, and then add the brown sugar, cumin, cardamom, turmeric, cinnamon and cloves and stir. Cook until this is very aromatic, about 1 minute.
Add coconut milk and tomatoes, and simmer. Add the coconut milk, stock and tomatoes. Stir to blend, bring to a boil, and then turn the heat to low and simmer gently until it thickens slightly, about 15 minutes.
Smash and add the potatoes. While the potatoes are still hot on the sheet pan, gently press them down to "smash" them. You can use a smooth-bottomed meat mallet, the bottom of a small sauté pan, or a Smood.Add the smashed potatoes and gently coat them well with the sauce. Add basil and season. Stir in the basil leaves and then season to taste with salt and pepper. (Here's How to Season to Taste.) Serve. You can serve immediately, but the longer the potatoes sit in the sauce, the more it will seep inside of them and the flavor will be more intense.