Grandpa Eli always requested this 4 ingredient treat for Sunday dinner. I whipped it up today and the pan was completely empty before anyone even asked what it was.

Slide the baking sheet with the pie into the preheated oven. Bake at 375°F (190°C) for 35–45 minutes, until the top is deep golden and set and you can see the molasses bubbling up thickly around the edges. The center will still look a bit jiggly, but it should not be sloshing like liquid when you gently nudge the pan.
Carefully remove the pie from the oven and place it on a wire rack or a folded kitchen towel on your counter. Let it cool at least 1–2 hours so the molasses layer can thicken and settle into that soft, gooey texture. The pie will slice much more cleanly once it has cooled.
Slice into wedges with a sharp knife, wiping the blade between cuts if the molasses is especially sticky. Serve slightly warm or at room temperature, right from the glass pie plate on your kitchen counter, just the way it would have been set out for Sunday dinner years ago.
Variations & Tips
For a slightly less intense flavor, you can use a milder baking molasses or mix half molasses and half dark corn syrup, though using all molasses keeps it closest to the old Amish style. If you like a deeper, bittersweet note, choose robust or blackstrap molasses, but be aware it will make the pie stronger and less sweet. Light brown sugar will give you a gentler caramel flavor, while dark brown sugar adds more richness and color. A pinch of salt or a light sprinkle of cinnamon and nutmeg stirred into the brown sugar before adding the butter is not traditional to the strict 4-ingredient version, but if you’re not worried about the count, it does add a cozy spice note. You can also use a homemade pie crust instead of store-bought as long as it’s unbaked and fitted into a glass pie plate so the bottom browns nicely and you can see the bubbling center. For a firmer center, bake a few minutes longer and cool completely before slicing; for a softer, gooier middle, lean toward the shorter baking time and serve just slightly warm. Food safety tips: Always handle the hot pie and glass pie plate carefully, using sturdy oven mitts and a solid baking sheet to avoid burns or spills. Allow the pie to cool on a heat-safe surface so the hot glass doesn’t crack from sudden temperature changes. Once fully cooled, cover leftovers and store at room temperature for up to 2 days or in the refrigerator for up to 4 days. Because this is a high-sugar pie with no eggs or dairy in the filling, it is fairly shelf-stable, but in very warm or humid weather, refrigeration is the safest choice.