Preheat the oven to 350°F (175°C) and line an 8x8-inch baking pan with parchment paper.
In a large bowl, combine oats, brown rice crisps, cornmeal, salt, baking soda, and ground flaxseed if using.
In a separate bowl, whisk together honey, melted coconut oil, and vanilla extract.
Pour the wet ingredients into the dry ingredients and stir until evenly coated.
Press half of the mixture firmly into the prepared baking pan.
Spread blueberry jam evenly over the pressed mixture.
Sprinkle the remaining oat mixture over the jam and press lightly to set.
Bake the bars for 18 to 20 minutes until edges are lightly golden.
Allow the bars to cool completely in the pan.
In a bowl, whisk together Greek yogurt, honey, vanilla extract, powdered sugar, and meringue powder if using until smooth and thick.
Drizzle the yogurt glaze over the cooled bars and let set before slicing.