Shred the cabbage and chop the spinach. If either is wet, squeeze out excess moisture with a clean towel or paper towels for crispier pancakes.
In a large bowl, whisk the eggs. Add the flour, milk, salt, pepper, and garlic powder; whisk until a smooth, thick batter forms.
Stir in the cabbage, spinach, and (if using) green onions until everything is evenly coated.
Let the batter rest for about 10 minutes so the flour can absorb moisture (helps the pancakes hold together).
Heat 1 tablespoon of oil in a skillet over medium heat until shimmering.
Scoop about 1/4 cup batter per pancake into the skillet and gently press to flatten. Cook 3–4 minutes, until the bottom is golden and the edges look set.
Flip carefully and cook 3–4 minutes more, until golden and crisp on both sides and cooked through.
Transfer to a paper towel–lined plate. Repeat with remaining batter, adding more oil as needed.
Serve hot and crispy. Great with sour cream or yogurt sauce, hot sauce, ketchup, or a simple side salad.