Plum Pie and the Pursuit of a "Perfectly" Set Fruit Pie

I taught a class this week about pies and tarts. It's a class that I have taught several times before, so there were no new recipes that had to be tested in order to prepare for it. I say "had to be tested" because I always have the feeling that things can be better (see my blog subtitle).  Often, even when I have a recipe that  produces consistent, good results, I continue to tinker away at it.

My victim this time around was my recipe for plum pie. I had a vague memory of tasting the pie the morning after I taught this class the last time (fruit pie makes an excellent breakfast) and thinking that the filling was a bit firmer than I would like. It wasn't gummy, it just didn't have that slight "droop" to the thickened fruit juices that one looks for in a perfect slice of fruit pie. Of course, being just a tad too firm is much preferable to being so runny that the juices run out of the sliced pie.

My original recipe called for two pounds of plums, or six cups of sliced fruit, thickened with two tablespoons each of cornstarch and tapioca. I occasionally make a mixed berry pie that uses these same ratios and I have always been happy with the consistency of the berry filling. Since berries tend to be juicier than plums I felt pretty safe decreasing the thickener to two tablespoons cornstarch and one tablespoon tapioca when I retested the plum pie.

When I cut into the pie about four hours after it came out of the oven, the juices were fairly liquid—the empty place in the pie plate, where the first two slices had been, quickly filled up with the juices from the adjoining slices. I was amazed at the difference one tablespoon of thickener had made. Because I knew that the starches would continue to set up over a twenty four hour period, the next day I cut a slice from the opposite side of the pie. It was perfectly set—soft fruit suspended in thickened, soft-set juices. Now I knew why my original recipe, that produced a pie that sliced perfectly for serving three or four hours after it was done baking, was too firm the next day.

As a last test, I made the pie again with two tablespoons cornstarch and one and one half tablespoons tapioca. At four hours after baking it had a fair amount of flow—but it didn't flood the plate. Some people might call this a perfect slice of pie.

At six hours, it was set well enough that only a little of the thickened juices oozed out—exactly what I was aiming for.

I suppose the lesson here is that the recipe was fine the way it was...unless you are a person like me who is a bit overly obsessed with getting things just right. But I have learned something about how thickeners work in fruit pies—learned by experience, not just from reading about it—and this is valuable to me. I have also learned that if I know when I am going to serve a pie, I can adjust the thickener to get the best results. Now I just have to lose the weight I gained from eating two pies....

Not everyone has tasted plum pie (or even heard of it), so it is a fun pie to teach. If you have never had plum pie, I hope you will give this one a try. If you like fruit pies, I think you will like plum pie. As in the plum crisp, the plums cook into a beautiful jewel-toned reddish purple. Also, because plums have a pleasant sweet-tart character the resulting pie is not too sweet and is very fruity tasting—just what a fruit pie should be.

Plum Pie

1 recipe Basic Pie Dough, rolled out as described for a double crust pie
3/4 c. sugar
1/2 t. allspice
pinch of salt
2 T. cornstarch plus 1 to 2 T. Tapioca (or 3 to 4 T. cornstarch)
2 lbs. plums, pitted, quartered and sliced cross-wise 1/2-inch thick (to make 6 cups fruit)—if using prune plums, simply pit and quarter
1 t. lemon juice
1 T. unsalted butter, cut into 8 pieces
Milk or half & half for brushing
Sugar for sprinkling (preferably coarse sugar)

Preheat the oven to 425°. Combine all of the dry ingredients in a small bowl. In a large bowl, combine the plums with the lemon juice and the dry ingredients. Immediately turn the fruit into the chilled crust, sprinkling any of the dry ingredients in the bottom of the bowl evenly over the fruit. “Dot” the pie with the butter.

Moisten the rim of the crust with water and top with the top crust. Crimp the edge, making sure the two crusts are well sealed. Cut several decorative slits to allow steam to escape. Brush the crust with milk and sprinkle with sugar.

Place the pie on the lowest rack of the oven. Bake the pie at 425° for 20 minutes. Turn the temperature down to 375° and bake for 20 minutes. If the edges are browning too quickly, cover them with a foil ring. Turn the temperature down to 325° and bake until the pie is golden and the juices are bubbling thickly in the center of the pie—another 25 to 35 minutes. Allow the pie to cool to room temperature before cutting (this allows the juices to “firm up”). If desired, re-warm the pie briefly just before cutting.  Serves 8.

Notes:

• Unfortunately pie baking is not an exact science. Your results are dependent upon your oven—so you need to get to know your oven. The goal is to have a fully cooked filling, a fully cooked bottom crust and a well browned top crust. Runny fillings and soggy bottoms are not inevitable. The regular temperature adjustments in this recipe are intended to maximize the likelihood that you will have success. But you must watch the pie as it bakes and adjust these temperatures and the timing of the temperature changes to fit your oven. The signal for the first reduction in temperature is when the crimped edge is golden brown and the bottom crust is beginning to show color—this will probably happen in the 15 to 25 minute range. In the next ten minutes or so, the crimped edge will probably begin to darken pretty quickly. I usually cover it with a foil ring as that begins to happen. If the juices begin to bubble over, slide a cookie sheet under the pie—but don't do this unless you need to since it will deflect heat away from the bottom crust. Finally, even if the juices are bubbling thickly (indicating that the filling is fully cooked and thickened) if the bottom crust is not golden brown (I use Pyrex pie plates so I can see if the crust is baked), keep the pie in the oven and turn the temperature back up to 375° to 425° until the bottom crust is done—this should only take another 5 to 10 minutes, but watch carefully to make sure the pie doesn't burn.

• This plum pie recipe is a “blue print” for any double crust fruit pie. Follow the same method—simply substitute 6 cups of berries, prepared stone fruit (pitted and cut into chunks or sliced), sliced apples or pears, or rhubarb for the plums; adjust seasoning (spices, citrus zest, extracts) and sugar (anywhere from 1/2 to 1 cup) to your taste. For berries and other very juicy fruits, use 4 T. thickener. For apples, use only 1 to 1 1/2 tablespoons of cornstarch (or substitute 2 to 3 T. of flour for the cornstarch).

Pâte Brisée (Basic Pie Dough)

2 1/2 c. all-purpose flour (300g)
3/4 t. salt
16 T. cold unsalted butter, cut into pieces (227g) )—for a more American-style crust, replace 4 T. of the butter with vegetable shortening
¼ to ½ c. ice water

Combine the flour and the salt in a medium-sized bowl. Rub the butter into the flour until the butter is in small pea-sized pieces. If you are using part vegetable shortening, rub the butter in first, then quickly rub in the shortening. Drizzle 4 T. ice water over the flour/butter mixture. Using your hands, fluff the mixture until it begins to clump, adding more water if necessary. If, when you squeeze some of the mixture it holds together, the dough is finished. Turn the dough out onto a counter and form into a mound. Using the heel of your hand, gradually push all of the dough away from you in short forward strokes, flattening out the lumps. Continue until all of the dough is flat. Using a bench scraper, scrape the dough off the counter, forming it into a single clump as you do. Divide the clump of dough into two pieces, and wrap each piece in plastic wrap, pressing the dough into a thick disk. Chill for at least 30 minutes.

To roll out a bottom crust, let one of the disks of dough warm up for a moment or two. Butter and flour a 9-inch pie plate and set it aside. Flour the work surface and the rolling pin. Begin rolling from the center of the dough outward. After each stroke, rotate the dough a quarter turn—always making sure that there is sufficient flour to keep the dough from sticking. Keep rolling and turning until you have a round of dough that is about 1/8 to 1/6 –inch in thickness. Using a lid or an upside-down bowl, trim the dough to form a 12-inch circle. Brush off the excess flour and fold the dough circle in half. Slide the outspread fingers of both hands under the dough and gently lift it and transfer it to the prepared pie plate. Unfold the dough and ease it into the pan being careful not to stretch it. Chill the pie shell for at least 1/2 hour.

Roll out the top crust. Trim the dough as for the bottom crust. Chill on a cookie sheet for at least 1/2 hour.