1. Measure out rhubarb. Defrost frozen rhubarb, then drain well and pat dry. Finely chop rhubarb. Preheat oven to 350F (180C). Lightly grease a 9 X 5 inch loaf pan. Stir rhubarb with 1/4 cup sugar & set aside. Finely grate peel from 2 oranges to amke about 2 TBSP., and squeeze out 1 cup juice. Measure 2 TBSP. of this juice into a dish. Stir in 2 TBSP. sugar & set aside to glaze loaf.
2. In a medium-size bowl, beat egg. Stir in remaining juice (1 cup minus 2 TBPS.), grated peel & vanilla. Measure flour, 3.4 cup sugar, baking powder, soda & salt into a large mixing bowl. Stir with a fork until blended & make a well in centre. Pour in egg mixture & cooled butter/ Stir just until evenly combined. Batter is very thick. Stir in rhubarb mixture & nuts just until evenly distributed.
3.Turn into prepared pan. Batter will almost fill the pan. Smooth top. Bake in centre of oven in preheated 350F (180C) oven until top is golden & a skewer/toothpick inserted into centre comes out clean, about 1 hour and 15-20 minutes. Place pan on a rack. Stir orange juice & sugar mixture, pour over top of hot loaf. Cool loaf in pan for 10 minutes. Then turn out of pan & place loaf on rack to finish off cooling. Loaf will keep well, covered, at room temperature for up to 2 days. Or wrap airtight & freeze. It's wonderful spread with cream cheese.