First, preheat oven to 350 degrees Fahrenheit and line an 8 inch by 8 inch baking pan with parchment paper.
In a large bowl, combine shortbread crust ingredients. Stir to combine.
Next, press 3/4 of this mixture into the bottom of the parchment lined baking pan. Set aside the remainder.
Bake for 12 minutes, or until just starting to turn golden around the edges. Remove from oven.
Then, in a medium skillet over medium heat, add blueberry jam ingredients. Bring to a light simmer.
Simmer for 4 to 5 minutes, using a spatula to break apart blueberries. Simmer until thickened. Then, remove from heat.
Pour this blueberry jam over the baked shortbread crust. After that, crumble remaining shortbread dough over blueberries.
Lastly, bake for 18 to 22 minutes.
Remove from oven and allow to cool at least 30 minutes before slicing.