Recipe courtesy of chef Michelle Bernstein.
Combine oil, rosemary, and red pepper in a small saucepan over low heat. Bring just to a simmer, and remove from heat. Let stand at room temperature until the oil has cooled and the rosemary has infused the oil, about 1 hour.
Strain oil through a fine sieve. Oil may be used immediately or stored in a covered container, refrigerated, for up to 3 days.