Heat 1 tablespoon olive oil in a medium skillet over medium heat. Add spinach in batches, stirring until just wilted, about 3 minutes total. Transfer to a colander and press out as much liquid as possible with the back of a spoon. Roughly chop and set aside to cool slightly.

Preheat oven to 350°F. Line a 9x5 inch loaf pan with parchment paper, leaving an overhang for easy removal. In a large bowl, whisk together flour, baking powder, salt, and pepper. Add 5 ounces of the crumbled feta and toss to coat in the flour mixture.

In a separate bowl, whisk eggs until foamy, then whisk in milk and extra virgin olive oil until combined.

Pour wet ingredients into dry ingredients and stir with a rubber spatula until just combined and no dry flour remains. The batter will be thick. Gently fold in the chopped spinach, being careful not to overmix.

Scrape batter into the prepared pan and smooth the top. Sprinkle remaining 1 ounce feta over the surface. Bake until golden brown and a toothpick inserted in the center comes out clean, 50 to 55 minutes. The internal temperature should read 200°F.

Let cool in the pan for 10 minutes, then lift out using the parchment overhang and transfer to a wire rack. Cool for at least 30 minutes before slicing - the texture improves as it rests.