So  for Thanksgiving I want to make roasted root vegetables.  All the recipes I have looked at call for potatoes which I don't want to use because we will be having mashed potatoes and candied sweet potatoes as a seperate dish. 

I wanted to use turnips but the one time I tried them in the recipe they came out bitter.  Am I doing something wrong?  Is there a trick to cooking turnips that I don't know about?  I'm also thinking of using parsnips and/or rutabagas.  Any tips about those vegetables.

Thanks.

Parsnips can be great. I always do a test run cook on things if I am nervous.

I peel turnips and rutabags, but I just clean my parsnips.   I chunk them, steam them and throw in a little salt, pepper and butter, or I roast them like Deb does above.  If they were bitter, they may have been green or too old.  You want to choose small to medium turnips and medium-sized rutabagas.  Parsnips should be creamy white, fairly uniform and not too thick. 

Here is a really great recipe from Cooking Light- you can always substitute something else for the sweet potato if you don't want to use it int his dish, since you are having a separate sweet potato dish.  Also, I don't have any fancy honey- so I just used regular honey from the grocery store.  I have made this several times- by "coarsely chopped", I just did a medium dice (probably about 3/4 inch).

Honey Roasted Root Vegetables (From Cooking Light)

Ingredients
2 cups coarsely chopped peeled sweet potato (about 1 large)

1 1/2 cups coarsely chopped peeled turnip (about 2 medium)

1 1/2 cups coarsely chopped parsnip (about 2 medium)

1 1/2 cups coarsely chopped carrot (about 2 medium)

1/4 cup tupelo honey

2 tablespoons olive oil

1/2 teaspoon salt

3 shallots, halved

Cooking spray

Preparation

Preheat oven to 450°.

Combine all ingredients except the cooking spray in a large bowl; toss to coat. Place vegetable mixture on a jelly-roll pan coated with cooking spray. Bake at 450° for 35 minutes or until vegetables are tender and begin to brown, stirring every 15 minutes.

I do similar recipes....the main thing with turnips is only buy them small.. The smaller the better; big means bitter, and so does old...If you can find golf ball size, or just a bit bigger, that's usually great. Most are baseball size or bigger, that's bad news for roasting. 

Little baby turnips are amazingly sweet when roasted, but they are hard to find.

parsnips are great when roasted. You might also consider adding a beet or two to the mix. (I know beets are love 'em or hate 'em... But they are very pretty!)

Beets are great when roasted. I am kind oif ho-hum about other ways (altho I love beet pickles) but a roasted beet is a very different thing...they are messy, tho; the juice will stain if you let it get on anything.

I use a recipe similar to the one Lesley posted, but with onions included.  Just peel and quarter them and toss in with the rest.  Very good, like the inside of an onion ring, but carmelization = way better.

Rutabagas - same thing as the parsnips - smaller is better generally. If you get a really big rutabaga it tends to be "woody". My husband loves mashed rutabagas.