Fried Apple Spring Rolls

Name: Fried Apple Spring Rolls
Ingredients: 1-2 tablespoons unsalted butter; 2 Teaspoons lemon juice; 1/3 Cup brown sugar, plus more to taste; 1/4 Teaspoon (generous) ground cinnamon or cassia; 3 Tablespoons dark rum; 1 Tablespoon finely diced crystallized ginger; 4 tart-sweet apples (1 1/3 pounds total), peeled, cored, and diced; 1 Cup cream cheese; 1/2 Cup mascarpone; 1 1/2 Teaspoon vanilla extract; 12 large Shanghai spring roll skins (lumpia wrappers); 1 egg, beaten well; Canola oil, for deep-frying; Powdered sugar, for garnish