Preheat oven to 375°F (190°C). Grease a 9" x 13"x 2" baking pan. Line with aluminum foil or parchment paper. Lightly grease the lining.
Place the flour, brown sugar, sugar, baking powder, and salt in the bowl of a food processor. Pulse until combined (about 4 pulses). Add the butter and pulse until mixture is crumbly. Add the oats and pulse until blended.
Set aside 1 & 1/2 cups of oat mixture.
Press the remaining oat mixture evenly into the bottom of prepared pan. Bake 10 minutes.
To make the topping:
Spread the jam evenly on top of the crust, leaving about 1/4-inch border around the edges.
Using an electric mixer on medium speed, beat the cream cheese, sugar, and vanilla extract until well-blended and smooth.
Drop small dollops (a teaspoonful or less) of the cream cheese mixture on top of the jam. Sprinkle the remaining oat mixture over the top of the bars.
Bake 30-35 minutes, or until bars are golden brown and set.
Cool completely before cutting into bars.
Notes
A food processor works very well for this recipe, but it isn't an absolute necessity. You can mix the crust in a large bowl with a pastry blender or a fork. The oats in the crust will just be full-size instead of partially broken by the food processor.
To store. Keep your blueberry jam oatmeal bars in an airtight container in the refrigerator for up to 4 days. You can place parchment paper between the layers to keep them from sticking.
To freeze. These blueberry bars can be frozen for up to 3 months in an airtight container or freezer bag. Let them thaw in the refrigerator before serving again.