Start your baking for holidays

Q I’d like to get a head start on holiday cooking and baking. What are some dishes that hold up well when made in advance?

A: In theory, you could start preparing as early as three months ahead of time, which is how long many cookie doughs will keep well in the freezer. Slice-and-bake cookies are particularly good to make in advance because you shape the dough into a log that fits neatly into the freezer: Just slice, bake and serve.

You could also freeze unbaked individual drop cookies, such as oatmeal or chocolate chip, on a baking sheet, and then transfer them to a freezer bag.

A basic pastry for a pie crust can also be mixed, rolled out to the desired thickness, and frozen right in the pie dish. It will keep this way for up to three months if well covered in plastic wrap and then in foil.

Alternatively, if you don’t want to leave the pie dish in the freezer, roll out the dough to fit into the dish, lay it on a baking sheet, and wrap the entire sheet in plastic wrap and then in foil before freezing.

Or make several batches at a time, separating each layer with parchment paper and wrapping as directed above.

When it’s time to make a pie, let the crust soften at room temperature until pliable (or in the refrigerator overnight), and proceed. In addition, some pies — double-crust apple, for example — can be assembled and frozen up to a month in advance.

Plus, they can go straight from the freezer into the oven — an amazing time-saver. (This make-ahead method won’t yield good results with custard-style pies, such as pumpkin, because the freezing and thawing can cause the delicately textured fillings to separate or weep.)

There are also plenty of side dishes that can be made ahead. Several types of relish, including cranberry sauce, can be prepared a couple of days early and refrigerated.

Many actually improve after their flavors have had a chance to meld. Gratins can often be assembled a day before baking. If using potatoes, submerge them completely in the liquid, such as cream or stock, to avoid oxidation (and the resulting gray color).

Even mashed potatoes can be prepared up to two hours before a meal. The trick is to put them in a heat-proof bowl, covered with a lid. Set the bowl over a pot of barely simmering water to keep the potatoes warm until serving time.

Q: What is “green” power? How can I bring it into my home?

A: This term refers to energy that comes from a renewable natural resource. The most common examples are the sun, wind and moving water, which can be harnessed in different ways to generate electricity. Until recently, homeowners had little control over where their electricity came from.

But more than 700 utility companies and other power suppliers in 44 states now let customers opt for an alternative type of power. (The provider should be certified by a third party, such as the Center for Resource Solutions.)

Green pricing programs are usually structured in one of two ways: Customers can buy blocks of the power at a fixed monthly fee or sign up for a combination of renewable and conventional electricity.

Green power costs anywhere from 0.5 cents to 2 cents more per kilowatt hour, on average, than conventional energy; percentage-based plans enable homeowners to be eco-conscious at a level that’s affordable. If you’re interested in making the switch, contact your utility company.

For more information, including a list of green-power providers broken down by state, go to the Department of Energy’s Green Power Network at www.eere.energy.gov/greenpower.

Q: Is it necessary to have a humidifier? How can I clean it properly?

A: When heating systems are running continuously, the air dries out and humidity levels drop, which can lead to parched throats, itchy eyes and respiratory problems. A humidifier helps keep the humidity at a comfortable level, usually 30 percent to 50 percent.

Cleaning the humidifier regularly is a must, as mildew and mold can grow in just a few days. Change the water daily, using distilled or demineralized water; both contain fewer minerals than tap water and will reduce buildup. After emptying the tank, dry it completely.

Clean the various parts a couple of times a week, following the manufacturer’s guidelines. In general, use a vinegar-water solution and disinfect with diluted bleach. After cleaning, rinse thoroughly and refill the humidifier with water.

Address questions to Ask Martha, care of Letters Department, Martha Stewart Living, 601 W. 26th St., Ninth floor, New York, NY 10001. Send e-mail to mslletters@marthastewart.com.