Combine sugar and salt in a small pot with blueberries.
Bring to a boil, and simmer until plump and soft, adding small amounts of water as needed. Bring to a boil, there should still be some liquid in the pot. Remove from heat, add cornstarch and stir quickly to incorporate and minimize lumps. Cook over a medium-low flame, stirring constantly until mixture bubbles and thickens (about 90 seconds). Meanwhile, toast oats, brown sugar and cinnamon with a little butter or oil in a pan. When golden and toasty, add on top of your blueberries