Step 1
Combine flour almond flour and salt for crust in a bowl.
Step 2
Combine sugar butter shortening and almond extract in the bowl of a stand mixer fitted with the paddle attachment; beat until light and somewhat fluffy. Add dry ingredients on low speed until just mixed about 1 minute; do not overmix.
Step 3
Drop dough into a 9x13-inch glass baking dish and flatten with floured hands building up a 1/2-inch edge on the sides so the filling doesn't stick to the dish. Transfer to the refrigerator to chill for at least 30 minutes.
Step 4
Preheat the oven to 350 degrees F (175 degrees C).
Step 5
Remove crust from the refrigerator and bake on the center rack of the preheated oven until golden at the edges and pale golden in the center 45 to 60 minutes. Remove from the oven and let sit on a wire rack until completely cool about 30 minutes. Reduce oven heat to 300 degrees F (150 degrees C).
Step 6
While the crust is cooling combine sugar flour lemon juice honey 6 egg yolks 4 egg whites lemon zest and baking soda for filling in a bowl. Whisk briefly to combine but don't overmix because we don't want to over-aerate the filling. Set aside 2 remaining egg whites for the meringue topping.
Step 7
Spread blueberries over the cooled crust then pour filling over top.
Step 8
Bake in the 300 degrees F (150 degrees C) oven checking frequently until filling is set 40 to 50 minutes. Remove from the oven turn oven off and let cool to room temperature on a wire rack about 30 minutes.
Step 9
Set an oven rack about 6 inches from the heat source and preheat the oven's broiler to high or 525 degrees F (274 degrees C).
Step 9
Combine 2 reserved egg whites from the filling with 2 egg whites sugar cream of tartar and salt for meringue in the top of a double boiler over simmering water. Whisk frequently scraping down the sides with a rubber spatula to avoid scorching until sugar has dissolved and mixture is hot 2 to 3 minutes.