Now, besides mushrooms (set them aside with ribs), start mashing the veggies (I did keep out a few carrots to serve on the side, this is up to you) & once they are starting to resemble a mash, add 1-2 Tbsp of butter & 1/4 – 1/2 C milk or cream. Season with salt & pepper. Cover to keep warm while you whip up the gravy.