Add 2 cups blanched almonds into a food processor, process on a low speed between 20 to 30 seconds, or until you end up with a powder like texture, transfer into a large bowl, add in ¼ cup granulated sugar and mix together

Crack 1 egg into a small bowl, transfer the egg yolk into a large bowl and set aside, whisk the egg whites and add into the bowl with the almonds & sugar, mix together, once you end up with a crumbly texture, get in there with your hands and push down on the mixture, as it comes together fold the mixture, continue with this technique until you end up with a paste like texture, then shape into a ball

Transfer the ball over some parchment paper, gently roll it out into the size of the casserole dish you´re using, mine was about 12 inches x 8 inches (30 cm x 21 cm), you want a thickness of about ¼ inch (.635 cm) thick from the almond mixture, then transfer into a casserole dish (making sure the parchment paper hangs on the sides so you can easily remove later), gently mold the mixture into the casserole dish, making sure it covers the entire bottom surface in a single flat layer, add into a preheated oven, bake only option (bottom heat), 175 C - 350 F

Meanwhile, crack in 6 eggs into the large bowl with the egg yolk that was reserved, whisk together, then slowly add in 1 cup granulated sugar while you continue to whisk, once the sugar has been added, finely grate in the zest of 1 lemon (making sure to not add any of the white pith), then squeeze in the juice of 4 lemons (about 1 cup / 240 ml) and give it one final whisk so everything is well mixed, set aside

After 14 to 16 minutes and the almond crust has a golden baked color on the edges, remove from the oven, slowly pour in the egg & lemon mixture over the crust, then add back into the oven with the same settings, bake only, 175 C - 350 F

After about 20 minutes the filling should be set, give the casserole dish a shake, if it´s firm it´s ready, remove from the oven (if it´s a little wiggly, leave it in there for a couple more minutes), let it sit at room temperature between 1 to 2 hours, then add into the fridge and cool for at least 2 hours (if you want to enjoy the lemon bars at room temperature, discard adding into the fridge)

Once the mixture has cooled in the fridge, cut the lemon bars into your desired size (I cut the mixture into 12 large lemon bars), making sure to wipe the knife with wet paper towels after each cut, to ensure you end up with clean cut lemon bars, sprinkle with powdered sugar (optional), enjoy!