In a large bowl, whisk together the eggs, garlic, pine nuts or slivered almonds, parsley, salt and pepper, Gruyere and Parmesan cheese, and onion.
Bunch the spinach leaves together, and using a chef's knife, chop it into thin strips. You want the spinach to be in small strips.
Add the spinach to the bowl and mix everything together. Add in the flour and stir until just combined. Add the raisins and fold them into the batter.
Heat a large deep frying pan or dutch oven with about 1-inch of vegetable oil on medium to high heat. I used about 1/2 a cup of oil. You want the oil to cover about half the height of the fritters since you will flip them to cook on the other side.
Once the oil is shimmering, take a large rounded spoonful of the batter and drop it into the hot oil. Repeat with the remaining batter. You may have to fry the fritters in two batches if your pan is not big enough, as you don't want to overcrowd the pan.
Fry for about 3-4 minutes before flipping each fritter to fry on the other side. You want to keep the oil hot and fry until golden brown on both sides.
Place on a paper towel-lined plate to drain the oil. Serve warm! A yogurt dip would be great to serve with these fritters.
