Preheat oven to 400 degrees. Wash and scrub potatoes, put them in a saucepan, cover with plenty of salted water. Bring to a boil and simmer for 20 minutes until half cooked. Drain cool slightly, quarter and place on a large baking sheet.
Wash Jerusalem artichokes, slice into 1/4 inch slices and place on sheet with potatoes. Add 4 crushed garlic cloves, 3-4 tablespoons olive oil, 2 tablespoons chopped sage and salt and pepper to your liking. Mix well with hands and place in preheated oven.
Meanwhile slice a lemon thinly and toss with vegetables after they have roasted for 20 minutes and roast another 10 minutes. Slice a big handful of cherry tomatoes in half. Add tomatoes and 1/2 cup pitted kalamata olives to roasting vegetables. Cook another 10-15 minutes longer, remove from oven and stir 2 tablespoons roughly chopped parsley. Serve and enjoy!