Celery-Root and Potato Latkes

Ingredients

• 1 large celery root (celeriac; 1 1/2 lb), peeled with a knife
• 1 1/2 lb large potatoes (about 3 large)
• 2 tablespoons fresh lemon juice
• 1 lb onions, quartered
• 2/3 cup all-purpose flour
• 4 large eggs, lightly beaten
• 1 1/4 teaspoons salt
• 1/2 teaspoon black pepper
• 1/2 teaspoon ground celery seeds
• About 1 1/2 cups vegetable oil