Dissolve The Yeast And 1/2 Teaspoon Of The Sugar Inn 1/2 Cup Of Warm Water. Add About A Cup Of The Flour And Stir Vigorously Til Smooth. Leave This Sponge-Batter For 30 Minutes Until Doubled In Bulk. Put The Remaining Flour In A Large Bowl, Add The Rest Of The Ingredients Except The One Egg Yolk, And Mix Will. Add The Risen Sponge. Work It With Your Hands And Add Enough Warm Water To Make A Soft Dough That Holds Together As A Ball. Knead For 10 Minutes Until Very Soft And Elastic. Pour 1/2 Tablespoon Of Oil In The Bowl And Roll The Dough Around To Grease It All Over. Cover The Bowl With Plastic Wrap And Leave In A Warm Place For 1 1/2 Hours Or Until Doubled In Bulk. Punch Down The Dough, Divide Into 6 Balls, And Place At A Distance Form Each Other On A Baking Sheet, On Parchment Paper. Leave Covered With A Cloth For 30 Minutes To Allow The Dough To Rise Again. Brush The Tops With Egg Yolk Mixed With 1 Teaspoon Of Water And Bake In A Preheated 400 F Oven For 30 - 40 Minutes Until Browned On Top. Tap The Bottom Of A Roll. If It Sounds Hollow, It'S Done. Cool On Rack.