Grease and flour one large bread pan (12x5 inches and 3 ½ inches high or 30x13 cm and 9 cm high) or two small ones. Preheat oven to 350°F (165-170°C).

In a large mixing bowl, beat butter and sugar until light and fluffy. Add lemon zest and beat in eggs, one at a time, until incorporated and scraping bowl between additions.

In a measuring cup, add lemon juice and vanilla extract to the buttermilk.

In another large bowl, whisk together flour, baking powder and salt.

Alternately add flour mixture and buttermilk mixture to the butter mixture, beating until incorporated and scraping bowl between additions. Fold in blueberries.

Pour batter into prepared pan(s) and bake for 60-65 minutes*, or until toothpick inserted near the center comes out clean.

Cool in pan on a wire rack for 10 minutes then remove from pan and cool completely on a wire rack.

Whisk the glaze ingredients together and pour over top of cooled bread. Store covered at room temperature for up to three days.