Finely dice tender stalks of rhubarb. Add 1/4 cup sugar and stir to combine. Let sit while preparing other ingredients.
Combine flour, salt, baking powder and orange rind. Stir to ensure orange rind is separated and covered well with dry ingredients.
Allow butter to come to room temperature. Cream butter and sugar together in stand mixer until well blended. Add egg, then orange juice and vanilla. Mixture will have a grainy texture.
Add dry ingredients to butter mixture and beat on low speed until just combined.
Add rhubarb mixture and beat on low speed until just combined.
Spoon into a loaf pan lined with parchment paper.
Bake in centre of oven at 350 degrees for 1 hour and 10 minutes. Check with toothpick to ensure no batter remains. If necessary, bake another 5 or 10 minutes.
Cool for 5 minutes before removing from pan. Then lift out and cool on a rack at least 1 hour before slicing.