Sausage and Sweet Potato Pie. Pic by Deb Lindsey for Washington Post.

SHEPHERD'S PIE meets hotdish in this fast comfort-food recipe that can make the most of leftover fresh herbs and sweet potatoes from the holiday. 

It is basic with just the two layers, but you could easily add a layer of cooked broccoli or cauliflower florets - or even add those to the saucy sausage mixture.

Recipe: Sausage and Sweet Potato Pie

4 to 5 servings

Ingredients

450 g sweet potatoes

Water

Kosher salt

Freshly ground black pepper

1/2 medium onion

450 g fresh sausage, your choice of flavor

Leaves from 1 stem rosemary or 3 stems thyme

1/4 cup flour

2 1/2 cups regular or low-fat milk (may substitute buttermilk)

Method

Peel the sweet potatoes, then cut into 3/4-inch chunks. Place in a microwave-safe bowl along with 1/4 cup water. 

Cover with plastic wrap (so the plastic is not touching the food). 

Microwave on HIGH for about 8 minutes, or until tender. Let sit for 2 minutes, then uncover and mash the potatoes in their bowl, seasoning them lightly with salt and pepper.

Meanwhile, preheat the oven to 400 degrees. Finely chop the onion. 

Discard any casings from the sausage, placing pinches of the meat in a 9- or 10-inch ovenproof skillet over medium heat. 

Cook for about 10 minutes, stirring to break up any large clumps, until the sausage loses its raw look. Use a slotted spoon to transfer to a plate, then add the onion to the skillet and stir to coat. 

Cook for about 5 minutes, or until softened.

Mince the rosemary or thyme leaves.

Sprinkle the flour over the onion, then stir to coat. 

Gradually pour in 2 cups of the milk, stirring with a wooden spoon, until thickened; over medium heat, this will take about 7 minutes. Return the cooked sausage to the skillet, stirring to incorporate. Taste and season lightly with salt and/or pepper. Remove from the heat; stir in all but a few of the minced fresh herbs.

Add the remaining 1/2 cup of milk to the sweet potatoes, stirring to form a fairly smooth mash. Spread evenly over the sausage mixture, making sure to cover it completely. Bake (upper rack) for 10 minutes, or until the potatoes are just set and beginning to brown on top.

Serve hot, sprinkled with the reserved minced herbs.

Serve with a steamed or sauteed green vegetable of your choice.

Adapted from the undated, spiral-bound "The Second Harvest Cookbook: Over 100 Inexpensive, Easy-to-Prepare Recipes for the Busy Cook"