In a small bowl sift together flour, 1/3 c of yellow cornmeal, sugar, baking powder, and salt. Make a well in the center of the dry ingredients. Stir together beaten egg, milk and cooking oil. Add all at once to the dry ingredients, stirring just till moistened. Line four 6-oz custard cups with paper baking cups. Fill 2/3rds full. Sprinkle a little additional cornmeal atop muffins. Micro-cook, uncovered, on 100% power about 1 1/2 minutes or till done, rearranging twice. (When done, the surface may appear moist but a wooden pick inserted near the center should come out clean.)