Preheat oven to 350 degrees Fahrenheit and adjust oven rack to the middle position.

Cut a sheet of parchment paper in half and then line bottom of an 8x8 inch pan with 1 sheet of parchment, lengthwise. Add the second sheet of parchment over the first sheet horzontally. The sheets should cross each other and have a small overhang. This will facilitate the removal of your bars from the pan. Alternatively, you can line the pan with aluminum foil the same way. If, and only if you are using foil, spray a light coating of vegetable spray.

In a medium bowl, add flour, almond flour, lemon zest, oats, sugar, and salt. Mix with your hands or with a fork to combine. Stir in the melted butter and vanilla extract. Mix with a fork until the mixture is well coated with the butter and all dry ingredients are well moistened.

Spread half the almond/flour/oat crumble mixture, covering the bottom of the pan. Press to form a thin crust that’s about ¼ inch in thickness.

Spread blueberry lemon jam over almond/flour/oat crumble mixture evenly using a small offset spatula. Sprinkle remaining crumble mixture over the blueberry lemon jam.

Place pan in the oven and bake until the crumble is a golden brown, about 30 to 35 minutes. Remove pan from the oven. Set on a wire rack and cool to room temperature. Use the parchment paper “handles” to remove bars from pan. Cut into squares and serve.

Makes about 16 small squares, 9 large.