Although asparagus is available to us year round, mid-April to June is the best time to eat these delicate spears. For optimal taste and nutrition, cook this veggie the day it's purchased. If that's not possible, keep it in the fridge for up to five days by wrapping the bottom of the stalks in a damp paper towel and placing them in a paper bag in the crisper drawer.
Storing asparagus well helps preserve its high content of folic acid (also known as folate) but it's also a good source of beta carotene, potassium, vitamin K and fibre.
One of my favourite ways of preparing asparagus is roasting it with a flavoured oil, a recipe that I've adapted from Shirley O. Corriher's book, Cookwise: The Hows and Whys of Successful Cooking (HarperCollins, 1997).
Flavoured oils are a subtle way to lower our fat intake; they pack more flavour than their plain cousins, so a little goes a long way. Neutral-tasting vegetable oils, including mild extra-virgin olive oils, can be infused with the essence of herbs, citrus zest or dry spices, to amp up the taste of roasted or grilled vegetables, meat, chicken, fish or seafood. They can also form the base of more intensely flavoured salad dressings, marinades and sauces.
But infused oils can be a breeding ground for bacteria. Any substance containing water or moisture-such as garlic, shallots, onion, citrus peel, fresh peppers, fresh herbs or spices-that's submerged in oil, may support the growth of the bacteria, Clostridium botulinum, which can cause botulism food poisoning. C. botulinum bacteria grows in conditions where there is no oxygen. Storing oil in a sealed container doesn't prevent contamination. What's worse, is there are no obvious signs, appearance, taste or smell-wise, of spoilage.
To be safe, make small quantities of flavoured oil at any one time and use it within a few hours. If made ahead of time, refrigerate the oil for no longer than a week. Never store home-made flavoured oil at room temperature. Although garlic infused in oil is especially known to cause harm, Health Canada states that it's safe as long as it's served immediately or stored in the fridge on a continuous basis and used within a week. Health Canada also recommends checking the label on commercially prepared garlic-in-oil products. If salt or acid is in the list of ingredients, then the product has been preserved. As long as you follow the directions for storing it, don't worry about food poisoning.
Roasted Asparagus with Lemon-Chili Oil
What You Need:
1 shallot, minced
1 teaspoon dried red pepper flakes
1/4 teaspoon ground black pepper
1/4 cup canola, grapeseed or peanut oil
1 teaspoon water
Finely grated zest of 3 small lemons 1 pound asparagus (about 24 to 30 stalks)
salt to taste
What To Do:
In a small saucepan, bring the shallot, red pepper flakes, black pepper and oil to a light boil, then reduce to a very low heat. Simmer for about 4 minutes. Remove the pan from the heat and let stand for 5 minutes. Stir in the water and the zest of 2 lemons (save the rest of the zest for garnishing). Let mixture stand at room temperature for one hour and then strain the oil into a small container.
Preheat oven to 500 Fahrenheit. Place an oven rack on the top shelf of the oven. Trim the asparagus stalks by snapping off the wooden ends and place on a rimmed baking sheet. Drizzle 3 to 4 teaspoons of prepared lemon-chili oil over asparagus and toss with hands until stalks are well-coated. Arrange stalks side by side so they aren't overlapping. Roast 6 to 7 minutes.
Remove from oven and spoon another 2 teaspoons of lemon-chili oil over the asparagus. Sprinkle with salt and 2 tablespoons of the remaining lemon zest. Serve right away.
Linda Watts is a registered dietitian. Send questions to email@example.com.