Rhubarb sauce is easy. Super easy.
Go pick the rhubarb, or find some at a nearby market. Look for firm stems/stalks, the redder the better. Cut away leaves, if you’re standing in the garden. These are from the market, and have “been around a while” so are a “brown” on the edges.
Wash. Trim ends, if necessary. You want stem only, no leaf parts whatsoever. Rhubarb leaves are poisonous. Stalks are fine, though.
Slice the stems into approximately 1/2 inch chunks. Drop into heavy-bottomed cooker. Add scant amount of water, maybe as little as 1/4 cup, only enough to keep the plant matter from scorching. Set the flame fairly low and stir frequently until the tissue begins to break down and yield liquid. Nudge up the flame and keep stirring.
After about 10-15 minutes, the chunks will have nearly entirely broken down. Turn off the flame and let sit for a few minutes. Add some white sugar, maybe 1/4 cup. Taste cautiously. The sauce might be very tart. Add a bit more sugar, stirring thoroughly. Taste again. Remember that the sauce will taste sweeter as it cools, so let it stay a bit tart.
I usually clap the lid on and let the rhubarb come to room temperature while the last of the tissues break down.
I hope this doesn’t sound complicated or gross. It’s a simple recipe and yields a lovely sauce. Eat the sauce plain, or put over ice cream.
If you want to make a pie, treat the raw rhubarb chunks like any fruit (e.g., berries, apples), adding some sugar and putting them into a crust for baking. Top crust optional; I’d use a crumble on top.