Preheat the oven to 350°F (175°C). Grease a loaf pan and line the bottom with parchment paper.
In a medium bowl, whisk together the all-purpose flour, baking soda, baking powder, and sea salt. If using poppy seeds, fold them in now.
In a large bowl, cream together the granulated sugar and Greek yogurt until smooth and fluffy. Add the eggs one at a time, mixing well after each. Then mix in the vegetable oil, lemon zest, and lemon juice.
Add the dry ingredients to the wet mixture in batches, stirring gently until just combined. Do not overmix.
Pour the batter into the prepared loaf pan and smooth the top. Bake for 50-60 minutes, or until a toothpick inserted in the center comes out clean.
Let the loaf cool in the pan for 10 minutes, then transfer to a wire rack to cool completely.
Notes
For an elegant touch, dust the cooled lemon loaf with powdered sugar. Serve with fresh berries or additional Greek yogurt.