1. Preheat oven to 230°C (450°F). Cut parchment paper or foil to make four 16 x 12-inch (40 x 30 cm) rectangles; set aside.

2. Trim tough ends from asparagus and cut each spear in half crosswise. Grate zest from lemon and set aside. Cut lemon in half lengthwise; cut one half into thin slices and remaining half into wedges. Set both aside.

3. Place each piece of salmon in the centre of a piece of parchment with long sides of salmon parallel with short sides of paper. Drizzle about 1 tsp (5 mL) of the cream over each piece of salmon. Top each with one-quarter of the lemon slices and 4 of the asparagus pieces; season with salt and pepper. Fold two short sides of parchment up to meet in the centre. Fold over several times to seal; fold each end into a triangle and tuck underneath. Place packages on a rimmed baking sheet. (They can be refrigerated for up to 4 hours).

4. Bake for 15 min or until packages are puffed and sizzling. Open one carefully to check for doneness. The salmon should have white juices formed on the sides and the asparagus should be tender-crisp. Refold and continue cooking if necessary.

5. While salmon is baking, in a small saucepan, melt butter over medium heat; sauté garlic for 1 min or until starting to turn golden. Sprinkle with flour; sauté for 1 min. Gradually whisk in remaining cream and bring to a simmer. Reduce heat and boil gently, stirring constantly, for about 3 min or until slightly thickened. Remove from heat. Stir in reserved lemon zest and capers. Season to taste with salt and pepper. Serve with lemon wedges.