This recipe is from the Williams-Sonoma Desserts "Best of the Kitchen Library" book that my daughter gave me as a birthday gift last year. It's not in the current version of this cookbook, so I'll reprint it here:
3 cups flour
1 tbsp. baking powder
1/2 tsp. salt
6 tbsp. softened, unsalted butter
1-1/3 cups granulated sugar
2 large eggs
2 tsp. vanilla extract
1 tsp. finely grated lemon or orange zest (I prefer orange)
1/4 sour cream
3/4 cup mil
2 cups blueberries, fresh or frozen
Confectioner's Sugar Icing
1/4 cup (2 tbsp.) unsalted butter
1 tbsp. water or juice (lemon or orange)
1/2 Confectioner's/icing sugar (regular sugar does not work)
Preheat oven to 350 degrees. Grease or no-stick spray a regular Bundt pan. This is a very heavy batter, so it needs the interior "space" that a Bundt shape provides to cook properly.
In a large bowl, mix flour, baking powder and salt, either by sifting or whisking - whisking is faster and neater! In large mixer bowl, beat the butter until light. Add sugar and beat until blended. Add the eggs, one at a time, beating well after each addition. Add the citrus zest and vanilla, followed by the sour cream. Reduce mixer speed to low and add the flour alternately with the milk, beginning and ending with the flour until just combined. The batter will be very thick.
Spoon half the batter into the prepared pan. You will need to even it out with your spatula. Sprinkle one cup of the blueberries over the batter and gently press them into the batter. Repeat with the remaining batter, followed by the second cup of blueberries.
Bake 50-60 minutes, until cake tester is clean. Time will vary based on your oven. Let cool completely on wire rack before removing from pan.
Citrus Icing Sugar Glaze
In a microwave safe dish, melt butter with citrus juice until fully combined. I've found this works better than adding the juice after the butter melts, since it incorporates more smoothly. Whisk in icing sugar and you're done!
On cooled cake, drizzle icing evenly over the top, allowing it to run over the edges. Cake should serve 10 or more depending on the size of your slices.