Preheat your oven to 425 F.
In small saucepan over medium high heat, add blueberries, sugar and lemon juice. Mash blueberries until only a few remain whole. Heat and stir until boiling. Remove from heat and allow to cool and thicken; set aside.
In a large bowl, whisk together flour, sugar, baking powder, and salt.
In a separate, medium bowl, whisk together yogurt, eggs, vanilla, milk and applesauce until fully incorporated. Mix the wet ingredients into the dry.
Spray doughnut pan with non-stick spray, filling each cavity ½ to ¾ths full of doughnut batter. Dollop two to three tsp of blueberry jam on top doughnut batter in each doughnut pan cavity. Using a knife swirl the jam into the doughnut batter.
Bake in oven for 9 minutes, or until light golden brown.
Allow to cool on wire rack.
In small bowl, whisk together the glaze ingredients. Pour over each doughnut, or dunk tops of doughnuts into glaze and turn right side up to set. Serve while still slightly warm.
