In a saucepan, boil milk and tea, cover and steep for 5 minutes and strain. Mix vanilla, yolks, sugar and corn starch together. Temper the milk by adding hot mixture to yolk/sugar mixture slowly whisking all the while. Return to heat in saucepan.
Simmer 5 minutes whisking constantly to avoid burning the bottom. Remove from heat, add butter and gelatin. Cool to room temperature.
Whip cream to soft peaks and fold together the cream and fennel mixture.
To assemble parfait, in a martini glass layer cream, then cake (see Spice Cake Recipe), then cream, then apple, fennel and huckleberries.