Preheat the oven to 350°F.
Coat a loaf pan with cooking spray.
Soak the dates and amaranth in the water for 15 minutes.
Meanwhile, beat the eggs, honey, and margarine. Stir in the flour, baking powder, pecans, and vanilla extract, mixing well. Stir in the drained dates/amaranth mixture. Pour into the prepared pan.
Bake for 1 hour and 15 minutes, or until a wooden pick inserted in the center comes out clean. Cool for 10 minutes in the pan. Remove to a rack, and cool completely.