In a medium sauce pan over medium-high heat, mix together blueberries, sugar, and lemon juice to a boil. Reduce heat to a simmer and allow the berries to cook down until tender - this should take about 10 minutes.

Mix your cornstarch with 2 tbsp of cold water and add to the blueberries, stirring constantly until thickened about another 1-2 minutes.

Meanwhile, prepare your crumb crust and topping. Line a 8 inch square baking pan with parchment paper and preheat your oven to 350 degrees.

In a large mixing bowl mix together oats, brown sugar, flour, cinnamon, nutmeg, and lemon zest. Using a pastry cutter, cut in butter until mixture is crumbly and you have pea sized bits of butter. Set aside in a cool place or in the refrigerator until your filling has cooled and you are ready to assemble your bars.

Once your filling has cooled, press about 1/2 of the crumb mixture evenly into the bottom of your pan using your hands and being sure that you press into all four corners.

Next, spread the blueberry filling evenly over top of your crust. Finally, top the blueberry filling with the remaining crumb for your topping, evenly coating the blueberry filling.

Bake for 40-45 minutes or until the crumb topping is a nice golden brown colour and the blueberry filling is bubbling around the outer edges.

Remove from the oven and allow to cool completely in the pan, before cutting into squares. Or You could serve it warm with a scoop of ice cream… DO IT!

Once cooled, use the parchment paper to life the blueberry bars from the pan and place on top of a cutting board. Cut your blueberry bars evenly to the size you want; I usually cut them into 9 or 16 equal squares.