Into a bowl sift together the flour, the baking powder, and the salt and stir in the poppy seeds. In a large bowl with an electric mixer cream the butter with the sugar and beat in the zest and the vanilla. Beat in the eggs, 1 at a time, and the milk and beat the mixture until it is combined well. Add the flour mixture and beat the batter until it is just combined. Divide the batter among 4 buttered and floured loaf pans, each 5 3/4 by 3 1/4 by 2 inches, and bake the breads in the middle of a preheated 350F. oven for 40 to 45 minutes, or until a tester comes out clean.

Make the syrup while the breads are baking:

In a small saucepan combine the lemon juice and the sugar, bring the mixture to a boil, stirring until the sugar is dissolved, and keep the syrup warm.

Poke the tops of the breads immediately all over with a skewer, brush them with some of the syrup, and let the breads cool in the pans on the rack for 5 minutes. Invert the breads onto the rack and poke all sides of them all over with the skewer. Brush the breads with the remaining syrup and let them cool, right sides up. Wrap the breads in plastic wrap and foil and let them stand overnight. The breads keep, wrapped well in plastic wrap and foil, chilled for 1 week or frozen for 1 month.

Makes 4 small loaves.