In a medium skillet, heat the oil. Add the panch phoron, cover and cook over high heat until the spices crackle, about 20 seconds. Add the dried chiles and cook, shaking the pan, for 20 seconds longer. Add the potatoes and cook, stirring, just until lightly browned in spots, about 5 minutes. Add the turmeric and season with salt. Cover tightly and cook over moderately low heat, stirring occasionally, until the potatoes are cooked through and lightly browned, about 15 minutes longer. Serve immediately.
Panch phoron, or Bengali five-spice powder, is available at kalustyans.com.