Heat oven to 350. Line an 8-inch square baking pan with non-stick foil or parchment paper.
In a large bowl, mix oats, flour, brown sugar, baking soda, salt and cinnamon. Add melted butter and stir with fork until evenly moistened (mixture will be very crumbly). Reserve 1/2 cup crumb mixture for topping; Press remaining mixture firmly over bottom of foil-lined pan. Bake 12 minutes to set crust.
Prepare Cream Cheese Filling: In bowl of electric mixer, beat cream cheese until smooth. Add sugar, vanilla and salt and beat well. Add egg and mix until combined. Pour filling over baked crust.
Prepare Filling: In a small saucepan, combine blueberries, sugar and cornstarch. Stir in lemon juice. Turn heat to medium and cook, stirring often, until mixture begins to thicken slight (it won’t be too thick) and clear (about 7 minutes). Remove from heat and pour over the cream cheese filling. Crumble reserved crumb mixture over top, then sprinkle nuts over crumb mixture.
Bake 30 minutes until top is browned and filling is bubbly. Let cool completely in pan set on a wire rack. When cool, chill for an hour before cutting. Lift foil by ends onto a cutting board. Peel off foil; cut into 12 bars. Store in refrigerator, but serve at room temperature.