Spinach Cake: simple, fast and delicious!

Ingredients:
2 cups fresh spinach (or 1 cup frozen spinach, thawed and drained)
1 ½ cups all-purpose flour
1 teaspoon baking powder
1/2 teaspoon baking soda
1/4 teaspoon salt
1/4 teaspoon pepper
1/2 cup olive oil (or any preferred vegetable oil)
2 large eggs
1/2 cup grated cheese (optional, but parmesan or cheddar works well)
1/2 cup milk
1/2 small onion (finely chopped)
2 cloves garlic (minced)
1 tablespoon lemon juice (optional, for extra flavor)
Directions: 

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