Someone on social media recently praised the glories of Pie Week, which could only mean that the usual Pie Day or Pi Day has now given way to an entire week of celebrating instead.

That’s my kind of inflation.

But who can blame people for wanting an excuse to indulge in even more crusted creations?

March 14 (or 3/14) commemorates pi, the mathematical constant rounded to 3.14, which is the ratio of the circumference of any circle to its diameter. In other words, no matter how small or large the circle, the ratio will always equal 3.14. It’s since turned into a perfect excuse to revel in pie.

Fun fact: Pi Day was founded in 1988 by physicist Larry Shaw, who worked at San Francisco’s Exploratorium for decades. How’s that for proud local lore?

You don’t have to be an expert in pi to enjoy pie. In fact, just use the day — or week — to treat yourself to a slice or slab, either homemade or from your favorite bakery.

I decided to go savory this year, and attempt something somehow both rustic and regal looking after spying “Mushroom Ragout in A Savory Crust” in the New York Times archives.

It’s a recipe from the late-great food writer Molly O’Neill. It’s essentially a mushroom pot pie — but one that definitely commands attention.

Being an older recipe, there was no accompanying photo of the finished dish. Still, I could imagine this two-crust pie filled to the brim with an assortment of mushrooms cooked in sherry as being something special, especially because fresh whole sage leaves get pressed into both the bottom and top crusts for an especially decorative look.

With a generous amount of butter in it, the dough is easy to work with and bakes up wonderfully crisp and flaky. The recipe calls for deep-dish pie pan. I only had a standard one, so I improvised and opted for a 9-inch spring-form pan instead with its taller sides. If you do the same, be sure to put a baking pan underneath in case any juices leak out.

For the filling, you will need mushrooms — a whole lot of them. The 3 1/2 pounds of shiitake, white mushrooms, and assorted wild mushrooms will look like a mountain. But remember, they will cook down considerably when you simmer them with the sherry, along with leeks, shallots, and plenty of butter. Instead of plain white mushrooms, I used cremini because I think they’re more flavorful.

The mushrooms simmer, covered on the stovetop, for 40 minutes. I opted to uncover the pot for the last 10 minutes of cooking because of the amount of liquid in the pot, which I wanted to evaporate further. You may find you want to do the same.

After the ragout is done, stir in bread crumbs and grated Parmesan, which will thicken up the mushroom mixture nicely.

Roll out half the dough, and press fresh sage leaves into it, before lining your pie pan or spring-form pan with it. Spoon in the mushroom ragout. Then, roll out the remaining dough, press more fresh sage leaves into it, and place atop the ragout, crimping edges to seal.

I found that it wasn’t easy to get the sage leaves to adhere well to the dough. So, I decided to try an egg wash, a beaten egg that I brushed over the top of the pie that I hoped would act as a glue to hold the leaves in place. It didn’t work completely, but it did help the leaves to stick a tad more. Plus, it gives the pie a nice glossy top. The directions didn’t say to score the top of the pie, but since every other pie I’ve ever made instructs to do so, I did the same, making three small slashes in the top crust. I added that to the recipe below.

The directions state to bake for 45 minutes. Because this is such a tall and bountiful pie, I found it took more like 55 minutes to 1 hour, so I amended that in the recipe, too.

When the pie is done, remove it from the oven and let it rest for at least 15 minutes before cutting. Even then, the pie will still be quite warm, so when you slice into it, the filling will tumble out a bit. If you wait even longer to cut into it, your slices will be neater looking.

But only the truly patient can wait that long on a pie right out of the oven. Me? I cut into after the 15-minute mark. I was rewarded with a golden, flaky crust that gave way to a melange of mushrooms that were earthy, hearty, and almost meaty. There’s no cream in the mushroom filling, and only a smidge of Parmesan cheese yet it tastes quite creamy.

It makes for a fitting and delectable way to honor Pi Day — any way you slice it.

Mushroom Ragout in A Savory Crust

(Serves 6 to 8)

For the ragout:

½ cup butter

4 leeks, chopped, rinsed and drained

5 shallots, minced

2 pounds white mushrooms or cremini mushrooms, quartered

¾ pound shiitake mushrooms, stemmed and quartered

¾ pound assorted wild mushrooms, quartered

1 tablespoon salt

1 teaspoon freshly ground black pepper

½ cup dry sherry

¾ cup bread crumbs (panko works fine)

3 tablespoons grated Parmesan cheese

For the crust:

1½ cups cold sweet butter

3½ cups flour, plus flour for dusting board

1 teaspoon salt

¼ teaspoon white pepper

2 egg yolks

½ cup water

½ cup sage leaves

1 tablespoon grated Parmesan cheese

1 egg, slightly beaten, for egg wash

For the ragout, melt the the butter in a large, heavy-bottomed pot over low heat. Add the leeks and shallots and cook until soft, about 10 minutes. Add the white mushrooms, cover and cook, stirring occasionally, for 20 minutes. Add the shiitake and assorted wild mushrooms, the salt, pepper, sherry and cook, covered, for 40 minutes, stirring occasionally. (If the mixture appears to have too much liquid, uncover pot for the last 10 minutes of cooking to allow more evaporation.)

Meanwhile, for the crust, slice the cold butter into a large bowl. Add the flour, salt and white pepper and, using a pastry cutter or two knives, work the flour into the butter. When the mixture resembles coarse cornmeal, form a well in the center. Beat together the egg yolks and water and stir into the flour and butter mixture until smooth. Divide into two balls and cool for 30 minutes in the refrigerator.

Preheat the oven to 350 degrees.

Lightly flour a board and roll out one batch of pastry. Gently press half the sage leaves into the dough. Line a deep dish pie pan with the dough and sprinkle it lightly with the 1 tablespoon of Parmesan for the crust. Stir the bread crumbs and 3 tablespoons Parmesan into the mushroom ragout and spoon into the pastry shell. Roll out the second batch of pastry, press the remaining sage leaves into the dough and top the pie, crimping the edges well. Brush on the egg wash, which will help the sage leaves to adhere better and give the pie a nice sheen. Using a paring knife, make three small slashes on the top of the pie to vent. Bake for 45 to 60 minutes until crust is golden. Remove from oven and let rest for at least 15 minutes before cutting. Serve.

Adapted from a recipe by Molly O’Neill in the New York Times

More Pie Recipes to Enjoy: Asiago Apple Galette or Pie

And: Cranberry Crumble Pie

And: Deborah Olson’s Classic Cherry Pie

And: Grapefruit Custard Pie

And: Matcha Cream Pie

And: Pear-Rosemary Muffin Tin Pies

And: Peach Hand Pies

And: Roasted Banana-Peanut Butter Cream Pie

And: Rosemary Pear Pie (Gluten-Free)

And: Tahitian Pineapple Pie