Sift flour into a bowl. Add yeast, sugar, and mix. Add salt and mix. Add warm water; begin with two cups and gradually add another quarter cup if needed.

Knead the ingredients for a few minutes until a dough begins to form. Add oil and knead for 10 minutes. Oil the surface of the dough and cover with a towel.

Put the dough in a warm place and let rise until doubled in bulk. This will take about one and a half hours.

Knead the dough for a few minutes. Divide into four equal parts and roll each part into a ball. Roll out each ball into a very long, narrow rectangle and roll it up jelly-roll style.

Attach the ends of two jelly rolls and twist them around each other to form a thick rope. Shape each rope into a ring and squeeze the ends together firmly. The hole in the middle will disappear during the rising and baking. Transfer the challah to a nine-inch baking pan.

Prepare the egg wash. Whisk the eggs with the oil and tea and spread over the challahs.

Sprinkle with sesame seeds if desired and allow to rise for 20 minutes in a warm place. Meanwhile, preheat the oven to 350 degrees Fahrenheit (180 degrees Celsius).

Bake the challahs for 35 to 45 minutes until golden brown. Remove from the baking pans and allow to cool.