• Preheat the oven to 350°F (180°C). Line an 8-inch square pan with non-stick parchment paper. Set aside.
• In a mixing bowl, add almond flour and lemon zest. Use your fingertips to rub the lemon zest onto the almond flour.
• Add quick oats, chia seeds, maple syrup, vanilla extract, and lemon juice.
• Stir with a rubber spatula at first, then lightly oil or wet your hands and squeeze the dough to bring everything nicely together into a sticky dough. If too dry or crumbly, simply add a teaspoon of water to stick everything together.
• Using a rubber spatula, press the batter into an even layer in the prepared baking pan.
• Sprinkle sliced almonds on top and press firmly with your fingertips to stick to the dough.
• Bake for 30 minutes at 350°F (180°C) until nicely golden brown.
• Let them cool down for 15 minutes at room temperature in the pan. Then lift the hanging parts of parchment paper and place them on a wire rack to cool for 1 hour. The cooling down firm up the bar.
• Transfer them another 1 hour in the fridge for another hour before cutting, so they are firm and nice.

Lemon Glaze - optional

• If you like a sweet lemon glaze, prepare the lemon glaze by stirring powdered sugar and lemon juice in a small mixing bowl. It should form a thick and creamy paste.
• Drizzle over the cold bar.
• Sprinkle extra lemon zest on top if you like its tangy flavor.
• Use a long, sharp knife to cut into 9 bars/squares.