Christmas morning evokes a lot of childhood memories: the gifts, the hugs, the merriment and, of course, the food.

In my household growing up, the annual rite of unwrapping presents under the tree came early after first light, followed by a big hearty breakfast at grandma's house across town. A fairly late breakfast, by that point.

Call it brunch, call it the after-party, call it what you will—it was always a big deal to me.

There were festive cookies of all kinds and steamy mugs of hot cocoa, fresh baked biscuits and jam, my mom's glorious cream cheese braid, and the main dish: grandma's egg casserole.

You hear a lot about the "joy of Christmas." This, to me, is the aroma and flavor of the holiday: rich and savory, warm and satisfying. Pure comfort. Like a frittata or quiche, packed with a lot more carbs, a meal unto itself and then some.

It was such a hit, she often baked two. There were many mouths to feed: uncles, aunts, cousins, in-laws—not to mention grandpa (we called him "Grandy")—good-hearted people, all of 'em. And I, then-nicknamed "the kid with the hollow leg," could nearly take down an entire casserole myself.

What made it so good? I dunno, stardust? My grandmother, Bonnie, was a lovely, 20th-century American queen, and the casserole, as a thing, was very of her era: economical, communal, and convenient. Your own mother, or grandmother, or great-grandmother, probably has a similar recipe.

Like much of her cooking, the egg casserole was nothing really fancy, but it was done with care—the delicious embodiment of beauty in simplicity.

The whole recipe comes down to five basic supermarket staples: a loaf of white bread, a quart of milk, a pound of pork sausage, a half-dozen eggs, a half-pound of shredded cheese. Add a dash of some common seasonings, like salt, pepper, dry mustard and Worcestershire sauce, which you probably already have on hand. Now, you're in business.

It's hard to imagine what these ingredients must have cost back in her day. I probably don't want to know. But even today, they remain relatively affordable.

A dozen eggs costs $3.59 on average right now, nearly twice as much last year. Luckily, you only need half for this. A loaf of basic white bread is $1.85. A gallon of milk is $4.22 (this requires just four cups). Pork is $3.69 and cheddar cheese is $5.93 per pound, respectively. All told, you can put together the whole dish for about $20 or less, if you already have the right spices.

Grandma liked to cut the crusts off the bread first, then cut each slice into eighths. This will be the foundation. Layer the greased casserole dish with bread pieces, add bits of cooked sausage, then top with cheese. Build a second layer in the same order.

Whisk together the eggs, milk and seasonings, then pour the whole mixture over the layered starch and protein. Stick it in the fridge to chill overnight, then transfer to the oven in the morning. Bake at 350 degrees for about an hour until golden brown.

You'll know when it's ready.

That smell, my friends, that's Christmas.