Set a rack in the upper middle of the oven and heat the oven to 400°F. Put a 10-inch oven-safe skillet and a medium bowl on the counter so they are ready.

Crack the eggs into the bowl.

Add the milk, dried oregano, salt, and black pepper to the bowl. Whisk until the eggs look smooth and evenly mixed.

Put the drained chickpeas and the chopped roasted red peppers near the stove so they are ready to go into the skillet.

Pour the olive oil into the skillet and set it over medium heat.

Add the chopped red onion to the skillet. Cook for 3 to 4 minutes, stirring a few times, until the onion softens and looks glossy.

Add the chickpeas to the skillet. Stir them with the onion and cook for 1 minute to warm them through.

Use the back of a wooden spoon or spatula to lightly mash about half of the chickpeas right in the skillet. Leave the rest whole so the frittata still has texture.

Add the chopped roasted red peppers to the skillet. Stir and cook for 1 minute, just until they are hot.

Sprinkle half of the feta over the chickpea mixture in the skillet. Spread the mixture into an even layer.

Reduce the heat to low. Pour the egg mixture into the skillet.

Use a heatproof spatula to gently move the chickpea mixture once or twice so the eggs settle all around it. Do not keep stirring after that.