Preheat oven to 400 degrees F (200 degrees C). Blend Spreadables butter with ginger, lemon zest, cumin, garlic, salt, and pepper until well combined; set aside.
Place chicken, back-side-up, with neck facing away on a cutting board. Use a chef's knife or poultry shears to cut along each side of the backbone. Remove and discard backbone. Turn chicken over; turn legs drumsticks-inward and press on breastbone to flatten. Place chicken, cut-side-down in a roasting pan.
Melt 3 tablespoons (45 mL) butter mixture; toss with potatoes, carrots, parsnips, and green onions. Scatter around chicken.
Carefully loosen skin over breast meat, legs, and thighs using fingertips. Spread remaining butter mixture evenly under and over skin of chicken.
Roast, basting occasionally, for 60 to 75 minutes (or until an instant-read thermometer registers 165 degrees F/74 degrees C in thigh and breast meat).
Cover and rest for 10 minutes. Carve chicken into portions and serve with vegetables.