Heat butter and sugar in large nonstick skillet over medium-high heat. Add apples; cook 10 to 12 minutes, until tender. Remove from heat; top with cinnamon. Let cool.
Heat sugar and water in medium-size heavy-bottomed saucepan (not nonstick) over medium-high heat until mixture turns amber, 12 to 15 minutes, swirling the pan occasionally, and not stirring. Carefully add cider; simmer until sauce is consistency of pancake syrup, about another 5 minutes (sugar should be completely dissolved). Stir in salt. Let cool.
Spoon about 1/3 cup filling into center of each crepe. Fold sides of each crepe around filling to form square package. Refrigerate the packages until ready to cook.
Heat butter and vegetable oil in large nonstick skillet over medium-high heat. Carefully add blintzes, seam side down; cook about 2 minutes per side or until crispy and browned. Remove to paper towels; gently pat the blintzes dry.
Serve immediately with caramel sauce and sour cream. If sauce thickens too much, microwave for about 15 seconds; sauce should be served at room temperature.