Pumpkin pie, a member of the custard pie family, is sometimes challenging to bake correctly. No, I don't mean getting the perfect pie crust or the right spices — although those things certainly don't hurt — I mean that custard pies are most often under- or over-baked. Pumpkin in particular is hard to read because of its dark filling. We tend to avoid poking and prodding pumpkin pie so that we can have a picture-perfect one.
Here are three signs that all good pie bakers know for determining the doneness of your prized pie.
1. The filling is darker and slightly puffed.
Around the suggested baking time in your recipe, your pumpkin pie's filling (and crust) should deepen in color. The filling should be slightly raised and there maybe some cracking around the edge where the filling meets the crust. The puff of the pie will relax as the pie cools, hiding many of the cracks as well.
2. It "jiggles" but doesn't "wiggle."
This is a technique that they actually teach in baking schools: Gently nudge your pie. The center of the pie should have some give — it jiggles — but it shouldn't wobble or wiggle. If the whole pie is wobbly, continue baking. When in doubt, bake the pie a little longer rather then risk an under-baked pie.
3. Test with a knife or thermometer.
When in doubt, you can always fall back on the classic cake test: A knife inserted into the edge of the filling comes out moist but clean. You can even look for a small crack along the edge to insert your knife with out ruining the top of your pie. A probe thermometer inserted into the center of the pie should read 175°F. (You can always cover that probe hole with whipped cream.)
A Note on Cooling
Out of the oven, cooling is another important step to ensure your pumpkin pie is done. Always cool the pie completely before slicing. Custard pies continue to cook as they cool; cutting into a warm pie may result in a small landslide of filling instead of a pristine slice.