Toss the chopped rhubarb and caster sugar in a flameproof roasting pan. Roast 25 mins. Steep a pot of Neat Jane's Tea Geisha Rose and Vanilla tea in boiling water for 10 mins.
Add tea (remember to filter tea leaves) to rhubarb and simmer for 5 mins until it thickens. Cool.
Cut pastry into quarters. Line 4x11cm round pie pans with trimming. Cool. Freeze for 10 mins. Re-roll scraps and freeze 10 mins. Reduce oven to 160 deg C.
Spoon cold filling into pies. Brush pastry rim with beaten egg. Cut extra pastry into strips and top pies with lattice patterns.
Trim edges and press with a fork to seal. Brush with extra beaten egg and sprinkle with sugar.
Bake pies for 45 mins on an oven tray on lowest oven shelf. Cover with foil if over browning.
Cool for 5 mins before transferring to a wire rack to cool completely.
Carefully lift pies from pan. Serve with whipped cream.