Preheat oven to 350°F (180°C). Grease and flour a 9 in. (1.5 L) bundt pan and set aside. Sift together flour, baking powder and salt; set aside.
Using an electric mixer, beat butter and cream cheese until smooth. Mix in ginger paste, orange zest and vanilla; slowly add sugar. Beat well at medium-high speed until light, about 5 min. Slowly add eggs, one at a time. Add flour mixture and blend until just incorporated.
Pour batter into prepared pan and bake on middle rack for 65 to 70 min., until a toothpick inserted into centre of cake comes out clean. Allow cake to cool on a wire rack before gently removing from pan and cooling to room temperature.
In a liquid measuring cup, blend together icing sugar, orange juice and poppy seeds until smooth. If glaze is too thick to pour, continue to add a 1/4 tsp of juice. Pour glaze over cake and allow to set; repeat five or six times more. Slice and serve or keep covered at room temperature for up to 1 week.
If you don't have a bundt pan, you can bake this cake in two 9 x 5 in. (2 L) loaf pans.