In a small saucepan, heat the oil over low heat to 175°. Add the ginger, star anise, cinnamon, shallot, garlic, Sichuan peppercorns and chiles and cook over moderately low heat until the oil reaches 225°. Simmer at 225° for 5 minutes, then transfer to a heatproof jar and let cool. Stir in the sesame oil.
Roasted peanut oil, as opposed to neutral peanut oil, smells richly nutty. Boyajin’s Fragrant Peanut Oil is available at specialty markets and from mingspantry.com.