Q: So many recipes call for yellow onions. But there also are white onions, sweet onions and red onions. Does it really matter if a recipe specifies a yellow onion and you use one of the others?

A: It does seem like there are an endless variety of onions. And since they each taste a little different, we can vary recipes by changing whether we use a scallion or a shallot.

Still, they are all onions. As long as the onion is the same basic type, such as a bulb onion, the results will be similar. A red onion may be more intense than a white onion, but the recipe will work with either one.

However, one big advantage to the yellow onion is price. Yellow onions are usually much cheaper than sweet onions or red onions, which is why so many recipes use them as kitchen workhorses.

Q: A chocolate cake recipe called for cacao nibs. What are those? Should I buy them raw or roasted?

A: Cacao nibs aren’t new, but they’re a new use for something very old. They’re broken-up chunks of cacao beans, which are used to make chocolate. They’ve been around for as long as people have made chocolate, but they’ve started turning up as an ingredient on their own.

They’re a little like chunks of roasted coffee beans, with a similar texture and a slight chocolate flavor. They’re usually used to enhance the chocolate flavor in things made with chocolate, such as chocolate bars, although they also turn up in savory dishes, such as salads.

Some sources call cacao nibs “raw chocolate,” and health food stores often sell cacao beans labeled as raw. But all cacao beans are at least minimally roasted or sun-dried. Culinary versions usually have been fermented, dried and roasted.

You can order nibs online, but you also can find them in gourmet stores, health-food stores and some well-stocked supermarkets.