Yes, fresh spinach will work just fine in this recipe. You'll need to wilt it first. Place it in a skillet with a tablespoon or so of water and stir until it has wilted. Remove it from the pan, let it cool, then squeeze out all the excess water using a clean tea towel, cheesecloth, or a piece of paper towel. Chop it finely. One pound of fresh spinach is approximately equal to 10 ounces of frozen spinach. Fresh spinach wilted down will equal about 1 1/2 cups. For this recipe, you'll need 5 ounces or about 3/4 cup of fresh spinach, cooked down.