• Preheat the oven to 350ºF. Lightly grease sides and bottom of loaf pan with butter or oil, or line with parchment paper. Set aside.
• In a large mixing bowl, use an electric mixer on medium-high speed to cream the butter until very light in color and texture. Use a spatula to scrape down the insides of the bowl as needed.
• Add the sugar to the bowl and continue mixing on medium-high for 2-3 minutes, until well combined. Add eggs, one at a time, fully incorporating one before adding the other. Continue mixing on medium speed until mixture is light and fluffy, scraping down the bowl as needed.
• In a small bowl, whisk together the flour, baking powder, and salt. With the mixer running on low speed, add 1/2 cup flour mixture and 1/4 cup milk to the mixing bowl at a time. When adding final 1/4 cup milk, also include vanilla or almond extract. Mix ingredients just until combined; avoid over mixing.
• Fold the frozen blueberries gently into the batter, then pour batter into the prepared loaf pan. Use an offset spatula or the back of a large spoon to smooth down the top of the batter.
• Place the pan on the center rack of the preheated oven. Bake at 350ºF for 60 minutes, until the top is springy and a toothpick inserted into the center comes out clean. Remove from the oven and let the cake cool in the pan for 5 minutes.
• Run a bread knife around the inside edges of the pan to loosen the cake. Turn the cake out onto a wire cooling rack to cool completely.
• If desired, drizzle glaze over the top of the cake, or serve topped with whipped cream, ice cream, or a dusting of confectioners sugar.

Butter Glaze (Optional)

• Add powdered sugar and melted butter to a small mixing bowl, and stir to combine using a silicone or wooden spoon. Pour in the milk and whisk well to combine.

  The glaze should be glossy and slightly thick, but still fluid. To reach a thinner consistency, add more milk, 1 teaspoon at a time. To thicken, add more powdered sugar.