Heat oven to 350°. Line a 9 x 5 x 3-inch loaf pan with nonstick foil. Set aside. In a medium bowl, whisk cornmeal, flour, flaxseed meal, baking powder and salt. In a large bowl, whisk oil, yogurt and eggs. Add other ingredients as directed below.
Mix dry ingredients into wet ingredients. Fold in any extras. Transfer batter to prepared pan and bake as directed. Cool completely on a wire rack.
Add 1/4 cup cornmeal, 2 tbsp flaxseed meal, 1 1/2 tbsp sugar, 1 1/2 tsp baking powder and 1/4 tsp salt to dry ingredients. Whisk 1/4 cup sour cream, 1/4 cup oil, 1 large egg and 1/3 cup milk into wet ingredients. Fold in 1/2 cup chopped scallions, 3 tbsp chopped cilantro and 3 tbsp chopped chives. Transfer to prepared pan and bake at 350° for 50 minutes.