Preheat oven to 350 F. Spray 4 ramekins with non stick spray or lightly brush with butter.
In a bowl, combine blueberries, cinnamon, lemon juice, cornstarch and water. Stir to combine. Leave to rest.
Meanwhile, prepare crumble by combining oats, salt, flour, sugar and butter. Mix until ingredients are well combined. It is easier to do this by hand.
Divide the blueberries between the 4 ramekins.
Divide the crumble between the 4 ramekins and spread on top of the blueberries.
Place ramekins on a cookie sheet and bake for 30 minutes, until the fruit is bubbly.
To make the whipped cream, combine heavy cream and powdered sugar in a bowl.
Beat with an electric mixer until thickened and whipped cream consistency.