In stand mixer bowl, combine yeast, sugar and warm water; let stand 10 minutes. Stir in oil, egg and warm milk. Add 3 cups flour, salt, dill and onion. Using a paddle attachment, blend on low speed for 30 seconds. Beat on medium speed for 3 minutes.
Switch to dough hook attachment. Gradually stir in enough remaining flour to make a soft dough. Knead until smooth and elastic, about 5 to 7 minutes.(NOTE: For hand mixing: following above steps, mix ingredients in large mixing bowl using a wooden spoon or dough whisk. Knead on floured surface until smooth and elastic.) Place dough in lightly oiled bowl and turn to grease top. Cover; let rise until indentation remains after poking dough with finger down to second knuckle, about 1 hour.
Prepare pan: Grease one 9×5-inch bread pan; set aside.
Punch down dough and turn out on lightly floured surface. Form into a smooth ball. Cover and let rest 10 minutes.
Roll or pat into a 14×7-inch rectangle. Starting with shorter side, roll up tightly, pressing dough into roll. Pinch edges and taper ends to seal. Place in prepared pan. Cover; let rise until indentation remains after touching.
Shape dough into loaf. Place in prepared pan. Cover and let rise until doubled in size, about 45 minutes.
Preheat oven to 375°F.
Bake for 30 - 40 minutes, until lightly browned and bread sounds hollow when tapped. Remove from pan; cool on wire rack.