Preheat oven to 350 degrees F. Lightly coat six 6-oz. custard cups or ramekins with cooking spray. Place custard cups in a 3-qt rectangular baking dish; set aside. In a heavy small saucepan, combine whipping cream and the 3 tbsp. sugar; heat over medium heat just until bubbly, stirring occasionally. Remove from heat; set aside.
Meanwhile, in a large bowl, combine egg yolks, maple syrup, vanilla and salt. Beat with a wire whisk or rotary beater just until combined. Slowly whisk hot whipping cream mixture into the egg yolk mixture.
Divide mixture among prepared custard cups. Place baking dish on oven rack. Pour enough boiling water into the baking dish to reach hallway up the sides of the custard cups.
Bake for 30-35 minutes or until mixture in custard cups appears set when lightly shaken. Transfer custard cups to a wire rack; cool. Cover and chill for at least 1 hour or up to 24 hours.
Before serving, let custard cups stand at room temperature for 20 minutes.
Meanwhile, for caramelized sugar -- in a heavy 8-inch skillet, heat the 1/4 cup sugar over medium-high heat until sugar begins to melt, shaking skillet occasionally to heat sugar evenly. Do not stir. Once sugar starts to melt, reduce heat to low; cook about 5 minutes more or until all of the sugar is melted and golden brown, stirring as needed with a wooden spoon. Quickly drizzle some of the caramelized sugar over each creme brulee. (if sugar starts to harden in the skillet, return to heat, stirring until melted). Sprinkle individual serving with toasted hazelnuts. Serve immediately.