Combine the eggs, fat, salt, and seltzer in a bowl, then stir in the matzah meal until well combined.
Cover the mixture and **refrigerate for at least 1 hour** to allow the meal to hydrate properly.⏱ 60 min
Place the chicken, vegetables, and half the dill in a large pot with 3 quarts of water.
Bring the pot to a boil, skim the surface foam, then **simmer for 90 minutes** until the broth is golden.⏱ 90 min
Remove the chicken and strain the broth, returning it to a clean pot and bringing it to a simmer.
Wet your hands with cold water and form the matzah mixture into **1-inch balls** using a light touch.
Drop the balls into the simmering broth, cover tightly, and **cook for 40 minutes** without lifting the lid.⏱ 40 min
Place the grated potatoes and onion in a clean kitchen towel and **wring out all excess liquid** firmly.
Transfer the dry mixture to a bowl and stir in the eggs, flour, and salt until combined.
Heat the oil in a large heavy skillet over **medium-high heat** until shimmering.
Drop 1/4 cup portions of the mixture into the oil and flatten them with a spatula.
Fry for **3 to 4 minutes per side** until they are deep golden brown and crispy.⏱ 4 min
Drain the finished latkes on paper towels and sprinkle immediately with extra salt if desired.