Preheat the oven to 400 °F. Set aside a large baking sheet, large enough that the parsnips will only be in one layer.
Wash then peel the parsnips. Slice the parsnips into equally sized sticks.
Toss the parsnips with the olive oil.
Place the parsnips on the baking sheet, then shake the sheet to coat the entire area with the olive oil from the parsnips. Make sure that the parsnips are in one layer.
Place into the oven and roast for 20 minutes, then shake the sheet pan again, turning over some of the parsnips with a fork if needed. You want to brown the parsnips on all sides if possible.
Roast for another 20-25 minutes, or until the parsnips are soft and golden brown.
Prepare the butter sauce by combining all of the ingredients into a glass measuring cup. Salt to taste if you don't use salted butter or if you simply like lots of salt.
Pour the sauce over the parsnips, shaking the sheet to make sure the butter sauce coats all of then evenly and roast for another 5-10 minutes, until the garlic pieces are golden brown and fragrant.
Notes
the recipe calculates that you eat all of the butter sauce, actual calories are lower than stated