Great Grandma Rose survived hard times with this 4 ingredient garden secret.

To stay true to Great Grandma Rose’s hard-times kitchen, this pie keeps to four basic ingredients, but you can still make small, practical adjustments. If your rhubarb is very tart (early spring stalks often are), you can add up to 1/4 cup more sugar without changing the character of the pie. If your rhubarb is on the sweeter side or you prefer a tangier bite, you can cut the sugar back to 1 cup, though the filling will be more sharp, the way many farm families liked it.

For a slightly firmer filling, especially if your rhubarb is very juicy, you can increase the flour to 1/2 cup; this will give you cleaner slices once cooled. A simple lattice crust instead of a solid top is also perfectly in keeping with old-fashioned pies and lets more steam escape, which can help the filling thicken a bit more.

If you must bake ahead, this pie keeps well at cool room temperature for about a day; after that, cover and refrigerate. For food safety, don’t leave the pie sitting out for more than 24 hours, especially in warm weather, as the moist filling and flour can encourage spoilage. Always wash and trim rhubarb carefully, discarding any leaves, which are not safe to eat due to naturally occurring toxins.

Use a glass or ceramic pie plate rather than metal if you can, as rhubarb is quite acidic and can react with some metal pans, giving an off flavor. Let the pie cool completely before covering or refrigerating so condensation doesn’t make the crust soggy. When reheating a slice, warm it in a low oven rather than the microwave to keep the crust flaky, just like it came out of that old farmhouse oven.