In large bowl, stir together brownie mix, flour, eggs, milk and oil until smooth.
Spray 10-inch skillet with CRISCO® Original No-Stick Cooking Spray; heat over medium heat. Pour about 1/4 cup batter onto center of skillet. Immediately rotate skillet until thin layer of batter covers bottom. Cook over medium heat about 1 minute, turning once, until top appears slightly dry.
Remove crepe to cutting board, flipping crepe over so first cooked side is facing up. Immediately roll up crepe; place on plate to cool. Cover with kitchen towel. Repeat with remaining batter.
In large saucepan, cook butter and granulated sugar over medium heat, stirring frequently, until sugar is dissolved. Stir in vanilla and lemon peel until well mixed. Add banana slices; gently toss until coated and slightly softened.
Fill 1 crepe at a time, keeping remaining crepes covered. Gently unroll crepe; fill with slightly less than 1/4 cup banana filling. Reroll crepe; place seam side down on platter. Repeat with remaining crepes. Top crepes with drizzle of caramel topping and dollop of whipped topping. Sprinkle tops lightly with powdered sugar; sprinkle with walnuts. Serve immediately.