Preheat oven to 350ºF (180ºC). Grease 9 x 5-in. (1.9 L) loaf pan; line bottom and sides with parchment paper. In bowl, whisk together flour, baking powder and salt. In separate bowl, use electric mixer on medium speed to beat butter and sugar until light and fluffy, about 2 min. Beat in eggs one at a time, incorporating each before adding next. Beat in lemon zest and vanilla. With the mixer on low, beat in 1/3 of flour mixture at a time, alternating with 1/2 the lemon juice at a time, finishing with flour mixture. Scrape bowl as needed between additions. Beat just until combined.
Scrape batter into prepared pan; smoothing top. Bake 1 hr. or until a tester comes out clean when inserted into centre of cake. Cool in pan 15 min., then unmold cake onto wire rack to cool completely, about 2 hr. (To make ahead, wrap and store cake at room temperature up to 2 days or wrap in heavy-duty foil and freeze up to 2 weeks before thawing and icing).
Meanwhile, whisk together icing sugar and milk. Pour glaze over cake. Garnish with cherries. Let icing set, about 15 min., before slicing. To cut cake into 16 pieces, slice in half length-wise, then make 8 cross-wise slices.
Use leftover pound cake in trifle, shortcake or French toast.