Preheat oven to 350 degrees F. Line an 8 inch square metal pan with foil and spray the foil with cooking spray (or use non-stick).
Mix the softened butter, sugar, and salt together with a wooden spoon. Stir in the oats. Add the flour and stir with the spoon until crumbly, finishing it off with your fingers if needed to make sure it’s mixed. Sprinkle in some water. Press crumbles into bottom of pan and bake on center rack for 15 minutes. Let cool.
Melt the butter in a medium saucepan. Stir in the tiny pinch of salt (if using) maple syrup, brown sugar and cream. Bring the mixture to a boil and boil for no more than 30 seconds. Remove the pan from the heat and stir in the vanilla and pecans. Pour the maple pecan filling over the crust, spreading it evenly with a spoon.
Bake the bars on the center oven rack for 15 minutes. Transfer the bars, in the pan, to a wire rack to cool thoroughly. Cover and refrigerate the bars for 1 to 2 hours before slicing.