In a large pot fitted with a deep-frying thermometer, combine 2/3 cup hot red pepper flakes; 4 garlic cloves, smashed and peeled; 3 scallions, cut into thin rings; 2 tablespoons minced fresh ginger; 2 1/2 cups corn or peanut oil, and 1/3 cup roasted sesame oil. Over medium-low heat, bring to a bubbly 225 to 250 degrees, stirring occasionally. Simmer 15 minutes, making sure the temperature does not rise above 250 degrees. Let cool. Scrape the oil and solids into a glass or plastic container and store tightly covered at room temperature.

Variations: Add any or all of the following before cooking: 1/3 cup Chinese black beans, coarsely chopped; the freshly grated zest of 3 large oranges; 1 tablespoon Sichuan peppercorns.