Preheat your oven to 180°C (350°F) and grease your muffin tin or line it with paper liners.
In a large mixing bowl, whisk together the all-purpose flour, baking powder, and salt until evenly combined. This creates a light, airy base for your muffins.
In a separate bowl, crack in the eggs and whisk them until they look slightly frothy, about 30 seconds. Then add the olive oil and milk, mixing until smooth and combined.
Finely chop the fresh spinach—aim for small pieces that will distribute evenly. Fold the chopped spinach into the wet ingredients, mixing gently until the green is evenly spread through the batter.
Crumble the feta cheese into small bits and fold it into the batter, ensuring it’s evenly distributed to give each muffin that salty, tangy punch.
Pour the wet mixture into the dry ingredients and gently fold together with a spatula. Do not overmix—just until the ingredients are combined, leaving a slightly lumpy batter.
Divide the batter evenly among the muffin cups, filling each about three-quarters full. Gently tap the tin on the counter to settle the batter and remove any air bubbles.
Bake in the preheated oven for 20–25 minutes, or until the muffins are golden on top and a toothpick inserted into the center comes out clean. Your kitchen will fill with a cheesy, slightly earthy aroma.
Remove the muffins from the oven and let them rest in the tin for 5 minutes. Then transfer them to a wire rack to cool slightly—this helps keep the crust crisp and the interior moist.
Serve warm or at room temperature. These muffins are best enjoyed fresh but keep well in an airtight container in the fridge for up to 3 days. Reheat briefly in the oven or toaster for a cozy, cheesy snack.
