Prepare parsnips by quartering, then use a vegetable peeler to shave out the center woody core from each quarter. Chop into pieces and place in a pot of salted cold water along with the potatoes. Bring to a boil and cook until tender. Drain, reserving 2 cups of the water, and place back in pot.
Lay a towel over the pot and cover with lid. This will absorb the excess steam from the potatoes.
Remove from heat and coarsely mash with a potato masher. Pour in the melted butter and continue to mash. Add the remaining ingredients, mashing until combined and smooth. If want a thinner consistency, stir in a bit of the potato water.
Use a spring-loaded ice cream scoop and form 12 mounds onto a parchment lined baking sheet. Spray the back of the scoop with a bit of oil,and use it to form a depression in each mound. Spray the tops of the wells with a bit more of oil and broil for 10 minutes or until light golden brown.