Prepare the Dough
In a large bowl, combine flour, sugar, salt, and yeast.
Add the warm plant milk and mix until a rough dough forms.
Turn onto a lightly floured surface and knead for about 15 minutes.
Halfway through kneading, work the coconut oil into the dough until smooth and elastic.
Shape into a ball, lightly oil the surface, place in a bowl, and cover.
Leave in a warm spot for about 1 hour or until doubled in size.
Make the Rhubarb Filling
Preheat oven to 200°C (390°F).
Divide rhubarb into thirds.
Slice one-third very thinly and reserve.
Cut the remaining rhubarb into 2 cm (1-inch) pieces.
Toss larger pieces with sugar, maple syrup, or stem ginger syrup.
Roast for approximately 10 minutes until softened.
Blend roasted rhubarb into a smooth purée and allow to cool.
Finely chop the stem ginger.
Shape the Buns
Punch down the risen dough.
Roll into a rectangle approximately 36 cm (14 inches) wide and 40 cm (15¾ inches) long.
Spread a thin layer of rhubarb purée over the dough.
Evenly scatter chopped stem ginger and thin rhubarb slices across the surface.
Roll tightly from the long edge to form a log.
Cut and Arrange
Cut into 9–12 equal buns.
Place swirl-side up in a lightly greased baking dish, leaving a little space between each bun.
Cover and allow to proof for another hour.
Bake
Preheat oven to 175°C (350°F).
Mix maple syrup and plant milk to create the glaze.
Brush over the buns.
Bake for 30–35 minutes until golden brown.
If browning too quickly, loosely cover with foil.
Brush hot buns with a little extra maple syrup immediately after baking.
Make the Icing
Mix icing sugar with 1–2 tablespoons rhubarb purée until smooth.
Adjust consistency as needed.
Drizzle over cooled buns.