Cut the parsnips smaller than the potatoes so they will finish cooking at the same time. Also, because the parsnip pieces are small, they're easier to mash.
2 cups chopped peeled parsnip
2 cups cubed peeled baking potato
1/2 cup half-and-half
2 teaspoons butter
3/4 teaspoon kosher salt
1/4 teaspoon coarsely ground black pepper
How to Make It
Place parsnip and potato in a saucepan, and cover with water. Bring to a boil. Reduce heat, and simmer 10 minutes or until very tender. Drain and return to pan. Add remaining ingredients; mash with a potato masher to desired consistency.