|Firmly packed light brown sugar||2⁄3 Cup (10.67 tbs)|
|Light corn syrup||1⁄4 Cup (4 tbs)|
|Cream of tartar||1⁄8 Teaspoon|
Combine all ingredients except vanilla in the top of a double boiler, set over boiling water, and beat with a rotary beater or portable electric mixer until mixture stands in peaks.
Off heat, add vanilla and continue beating until mixture will hold deep swirls.