Adjust oven rack to middle position and heat to 180C/350F. Grease an 8½ x 4¼-inch loaf pan.
In a medium bowl, sift together 1 1/2 cups flour, baking powder, and salt. Set aside. In another small bowl, toss together sugar and lemon zest until combined.
In a standing mixer fitted with the paddle attachment, beat together butter and lemon-sugar mixture on medium speed for 3 minutes, until light and fluffy. Occasionally scrape down the sides and bottom of the bowl. Add eggs, one at a time, beating well after each addition. Beat in vanilla extract. Add half of the flour mixture and beat on low speed just until combined. Beat in heavy cream and lemon juice just until combined, followed by the rest of the flour mixture. Do not over mix. In a small bowl, toss blueberries together with 1 tablespoon flour (to prevent them from sinking to the bottom while baking), then gently fold into batter.
Scrape batter into prepared pan and smooth the top. Bake for 45-60 minutes, or until a skewer inserted into the center of the cake comes out clean. If the top is browning too fast while baking, cover pan loosely with aluminum foil. Allow cake to cool for 10 minutes, then remove from pan and set on a wire rack. Allow to cool completely.
To make the glaze: In a small bowl, combine powdered sugar, lemon juice, and milk, and whisk until smooth. Add more milk or lemon juice as necessary until you get a thick yet pourable consistency. Pour over top of cake and let drizzle down the sides. Allow glaze to set, 15-30 minutes.
Store cake in an airtight container at room temperature for up to 3 days, or in the refrigerator for up to 5 days. Cake can be frozen without glaze for up to 2 months. Once thawed, make the glaze.