Source : Webster's Revised Unabridged Dictionary (1913)

Simnel \Sim"nel\, n. [OF. simenel cake or bread of wheat flour,
   LL. simenellus wheat bread, fr. L. simila the finest wheat
   flour. Cf. {Semolina}.]
   1. A kind of cake made of fine flour; a cracknel. [Obs.]

            Not common bread, but vastel bread, or simnels.
                                                  --Fuller.

   2. A kind of rich plum cake, eaten especially on Mid-Lent
      Sunday. [Eng.] --Herrick.

Source : WordNet®

simnel
     n 1: a crisp bread of fine white flour
     2: a fruitcake (sometimes covered with almond paste) eaten at
        mid-Lent or Easter or Christmas