This recipe caused a ruckus in my culinary class when my professor questioned me about what was specifically used in this recipe....HAHA! I told him that I was not sure, but I was at an international market and purchased something that was similar to a tube, which is in the potato family. It was smaller in size than a regular sweet potato, however, I am pretty sure that is was an Asian sweet potato of some variety. We both thank Simply Ming for this one...
In a large heavy saucepan, combine the oil with the ginger and heat over medium heat until the oil is fragrant and the ginger just begins to color, about 8 minutes. Remove from the heat and cool completely, about 20 minutes.
Meanwhile place a large heavy saute pan over medium heat. Add the curry powder to the dry skillet and toast, stirring until the curry powder smokes lightly 8-10 minutes. Whisk in the ginger and oil, remove from stove, and cool completely 30-40 minutes.
Transfer to a container and allow the mixture to stand until the oil and curry powder have separated which will take about 4 hours. Scoop out the risen spices from the oil, and it is now ready to use.
You can peel the potatoes or leave the skin on since it is your preference. I choice to remove my skins from the potato. Then slice off the ends of the potato and cut into 1/4 - 1/2 inch thick fries or julienne.
In a large bowl, combine the 1 cup of Curry-Ginger Oil and all but 2 tablespoons of the scallions. Add the potatoes, season with salt and pepper, and toss well.
Place a heavy sheet pan in the oven and heat to 400F. Remove the pan, dump the fries onto it, and using a spatula, separate the potatoes. The sheet pan should be hot enough for the potatoes to sizzle, if not, remove them and heat the pan longer.
Bake the potatoes until golden brown, 10-15 minutes. Check periodically to make sure potatoes aren't browning too quickly.
Use a spatula to turn the potatoes so that the uncolored side is golden, cook 10-15 minutes more. If the potatoes are browning too rapidly then lower the heat to 350F. Check with a toothpick for doneness, easily penetrating the potato.
Arrange the potatoes on a serving platter, toss with the remaining scallions and some remaining oil, check seasoning and serve hot.