Preheat the oven to 175°C / 350°F using the top and bottom heating mode.

Grease a bundt pan thoroughly with shortening, vegetable oil spray, or softened butter. Ensure the grease reaches all grooves and detailed areas of the pan.

Sprinkle flour generously over the greased pan, then tap out any excess flour. Set the prepared pan aside.

Sift the plain flour, baking powder, baking soda, and salt into a mixing bowl. Set aside.

In a separate bowl, toss the blueberries with 1 tbsp flour until evenly coated. If using frozen blueberries, do not thaw them before coating.

In the bowl of a stand mixer fitted with the paddle attachment, or using handheld beaters, beat the butter and caster sugar on medium-high speed for 4 to 6 minutes, or until light and fluffy. Scrape down the sides of the bowl once or twice as needed.

Add the eggs one at a time, beating well after each addition. Ensure each egg is fully incorporated before adding the next.

Add the vanilla extract, lemon juice, and lemon zest. Beat for approximately 30 seconds, or until the mixture is combined.

Reduce the mixer speed to low. Add the flour mixture in three additions, alternating with the sour cream. Begin and end with the flour mixture.

Mix each addition only until combined. Do not overmix. The batter should be smooth, thick, and creamy.

Using a rubber spatula, gently fold the flour-coated blueberries into the batter until evenly distributed.

Spoon the batter into the prepared bundt pan. Level the batter and smooth the surface with a rubber spatula.

Alternatively, add one-third of the batter to the pan, spread a layer of blueberries over the batter, and repeat until all batter is used. Finish with a thin layer of batter to cover the blueberries.

Bake in the center of the oven for 50 to 55 minutes, or until the cake tests done.

To test for doneness, insert a metal skewer or cake tester into the center of the cake. If it comes out clean, the cake is fully baked. If it comes out sticky or covered in batter, continue baking for an additional 5 to 7 minutes and test again.

If the cake browns too quickly before it is fully baked, cover it loosely with a sheet of aluminum foil.

Remove the bundt pan from the oven and allow the cake to cool in the pan for 15 minutes.

Carefully invert the cake onto a wire rack and allow it to cool completely.

Once the cake is completely cooled, prepare the lemon glaze. In a bowl, combine the confectioner’s sugar, melted butter, lemon juice, and salt.

Stir until the glaze is smooth and pourable.

Spoon the lemon glaze over the top of the cooled bundt cake. Use the back of the spoon to gently guide the glaze over the sides.

If the glaze thickens too quickly, microwave it on a low power setting for 5 to 10 seconds, or until it reaches the desired consistency.

Allow the glaze to set slightly before slicing and serving.