Preheat oven to 400°F (200°C) and line a baking sheet.
In a saucepan, bring butter, water, and salt to a boil. Stir in flour, return to heat, and mix into a dough ball.
Cool slightly, then beat in eggs one at a time until smooth.
Pipe or spoon onto the sheet in 1.5-inch mounds.
Bake for 25–30 min until golden. Cool completely.
Cook rhubarb, sugar, and cornstarch until thickened. Cool and stir in vanilla.
Whip cream and powdered sugar to stiff peaks. Fold in cooled rhubarb.
Whisk glaze ingredients until smooth.
Slice puffs, fill with rhubarb cream, top with glaze. Serve fresh or chill up to 2 hours.