To make the dressing, slowly drizzle the olive oil into the vinegar or lemon juice while whisking constantly. The dressing should start to thicken. Add the salt, pepper to taste and maple syrup. Crush the garlic cloves, remove the skin and add to the dressing.
Preheat the oven to 400° C with the rack in the middle.
Peel and cut your vegetables and place them on a baking sheet lined with parchment paper. Sprinkle with salt, pepper and drizzle with the olive oil. Toss well and spread them evenly on the baking sheet.
Bake for 20-25 minutes, turning occasionally until tender and lightly browned. If you like them extra crispy, leave them in for an additional five minutes.
Cook the lentils while the vegetables are roasting by bringing a large pot of water to a boil. Salt the water and add the lentils. Simmer according to package instructions until al dente or just done (not mushy), about 15-25 minutes.
Drain the lentils well and add them to a large bowl. Remove the garlic clove from the dressing and add it to the lentils. Toss gently until all the lentils are well coated.
Add the roasted vegetables and chopped parsley to the bowl and toss gently.
Crumble the cheese on top, if using and serve warm or at room temperature.