Preheat oven to 325° F. Butter and flour two 9 x 5-inch metal loaf pans, knocking out any excess flour.
Finely grate enough zest from lemons to measure 2 tsp and squeeze enough juice to measure about 1/2 cup. Into a bowl sift together flour, baking powder, and salt.
In a large bowl with an electric mixer beat together butter, 2 cups sugar, and zest until light and fluffy. Beat in eggs 1 at a time, beating well after each addition. With mixer on low speed add flour mixture and milk alternately in batches, beginning and ending with flour mixture and beating just until batter is combined well. Beat in poppy seeds and 1 Tbsp lemon juice and divide batter between loaf pans, smoothing tops. Bake loaves in middle of oven until a tester comes out clean, about 1 hour.
While loaves are baking, in a small bowl stir together remaining lemon juice and remaining 1/2 cup sugar until sugar is dissolved.
Cool loaves in pans on a rack 15 minutes. Run a thin knife around edges of pans and invert loaves onto rack. Turn loaves right side up and pierce tops all over with a thin skewer. Repeatedly brush lemon glaze over tops of loaves until all of glaze is absorbed.
Cool loaves completely. Tea bread keeps, wrapped in wax paper, in an airtight container at room temperature 4 days or, wrapped in foil and frozen, 1 month.
Makes: 2 loaves