In a large skillet over medium-high heat, brown beef, then mix in onion, garlic, 2 tablespoons soy sauce, 1/2 teaspoon salt, 1/2 teaspoon pepper, 2 tablespoons sherry, and ginger. Continue to saute just until onions are tender. Transfer mixture to a bowl and set aside.
In the same skillet, saute cabbage with water, 1 tablespoon oil, sugar, and remaining soy sauce, sherry, salt, and pepper. Continue to saute until cabbage is crisp-tender, about 5 minutes. Return meat mixture to pan and stir together with cabbage over low heat until heated through. Remove from heat.
Pour oil into a deep pan and heat to 350 degrees F (175 degrees C). Fill each egg roll wrapper with approximately 1/4 cup of filling and roll up according to package directions. Fry in preheated oil until golden brown. Drain on paper towels and serve hot.