In a large bowl or the bowl of a stand mixer, add yeast and warm water and let sit for 5 minutes or until foamy. Stir in sugar, oil and salt. Whisk in 2 eggs plus 1 egg yolk, one at a time, until fully combined. Using a wooden spoon or a dough hook (if using a stand mixer) begin to add the flour in 1 cup increments. Keep adding flour until a smooth dough forms. Dough should be sticky but still come away from the sides of the bowl. If the dough seems too wet, add another 2 tbsp of flour and knead again to test consistency. Knead dough for 5-6 minutes until dough is smooth and holds together. Oil a large bowl with olive oil and place dough inside. Cover with plastic wrap or a kitchen towel and let rise in a warm, draft-free place for 90 minutes or until doubled in size. Punch dough down, turn it over in the oiled bowl, and recover. Place in the fridge to rise overnight. When ready to bake, remove from the fridge in the morning and let it come to temperature on the counter for 2 hrs. Turn the dough out onto a lightly floured surface and divide into either 3 or 6 pieces, depending on how you want to braid the loaf. Roll pieces into 12 inch ropes, then braid as desired. If doing a 6 strand loaf, line up all six strands vertically, then follow the “over 2, under 1 rule” Take the leftmost strand, go over the next two strands, then under 1 strand, and repeat to the end of the line. Start the process over again with the new leftmost strand, and repeat until the loaf is braided. Transfer dough to a parchment lined baking sheet and loosely cover to rise 1 more hour. Preheat the oven to 375 and whisk the last egg with 1 tbsp water to make an egg wash. Let bread cool for 20 minutes before removing to a wire rack to cool completely. Brush loaf liberally with egg wash, then bake for 20 minutes. Carefully remove from oven, brush again with the egg wash, and return to the oven to bake another 20-25 minutes or until golden brown.