Mix all the ingredients together in a small bowl with the exception of the butter. Adjust salt and pepper to your taste.
Preheat oven to 425 degrees Fahrenheit.
Fold the parchment paper in half and make a crease. Generously butter the bottom half of the parchment, leaving an inch from the edge clean.
Heap the vegetables into the center of the buttered area and spread them over the entire half, carefully leaving the edge free. Dot with a few small pieces of butter.
Fold the top half of the paper down and tightly fold and roll the two halves together to form a seal. Now fold and roll the outside edges of the paper inward until everything is sealed into a pocket. It will look rustic, and this is exactly the fun of it, so don’t worry. Just get it sealed.
Place the packet on a baking tray and bake for approximately 25 minutes. The packet will begin to brown, and once you see this you will know that the roasted vegetables are ready.
It is very possible to double this recipe and still fit everything into the 15x15-inch parchment paper. In fact, this is what you see in the photographs. Be creative with your choice of vegetables, and your seasoning. Don’t like sage? No problem. Use oregano. Add some chilis if you like it spicy. Do what strikes your fancy. See my companion post Butternut Squash & Leek Baked in Parchment for more ideas.