1. Place blueberries, sugar, and salt in a small saucepan. If using frozen blueberries, add 2 tablespoons of water. Bring to a boil; reduce heat to a simmer and cook, stirring often, until thickened, about 15 minutes. Allow to cool while making the cake batter.
1. Spray a 10-cup bundt pan generously with pan spray. Put in freezer until ready to use. Preheat oven to 350 F.
2. Sift dry ingredients together in a large bowl. Stir in lemon zest.
3. In the bowl of a stand mixer fitted with the paddle attachment, whip the butter until fluffy and soft, 1-2 minutes. Add sugars; cream until light and fluffy, another 2-3 minutes. Add eggs one at a time, scraping bowl with a spatula in between each addition. Stir in vanilla.
4. Combine lemon juice & yogurt in a liquid measuring cup or small bowl.
5. Alternate dry ingredients with yogurt mix, starting and ending with flour mix. Scrape down bowl with spatula as necessary.
1. Remove prepared bundt pan from freezer. Pour half of cake batter into pan and use a spatula to even it out.
2. Create a trough in the batter using the back of a spoon. Pour about 3/4 of the blueberry jam evenly into trough. Using a knife, swirl the jam with the cake batter. Repeat this process with remaining batter and jam.
3. Bake until toothpick inserted in the center of cake comes out clean, about 45-55 minutes.
4. Allow to cool for about 20 minutes. While still just slightly warm, invert cake onto a cooling rack. Allow to finish cooling completely.
1. Puree the blueberries using a food processor or emulsion blender. Strain through a fine-mesh sieve to remove skins. You should end up with 3-4 tablespoons of blueberry juice.
2. Stir together powdered sugar, lemon juice, and 3 tablespoons of blueberry juice. You may need to add a little more juice or powdered sugar to achieve the desired thickness. You want it to be thick but pourable.
3. Spoon glaze onto cooled cake, allowing it to drip over the sides.
Serve and enjoy!