Prepare all of the ingredients as directed.
Preheat the oven to 350°F (177°C). Line a baking sheet with parchment paper.
Make the flax mixture. Combine the ground flaxseed and warm water in a small bowl. Stir and let stand for 5 minutes to thicken.
Combine the dry cookie ingredients. In a medium bowl, mix the rolled oats, all-purpose flour, almond flour, baking powder, baking soda, cinnamon, and sea salt.
Combine the wet ingredients. In a separate bowl, stir together the almond butter, oil, maple syrup, vanilla extract, and thickened flax mixture until well combined.
Make the cookie dough. Add the wet mixture to the dry ingredients and stir until just combined. Gently fold in the chopped walnuts, blueberries, and lemon zest.
Shape the cookies. Divide the dough into equal portions on the prepared baking sheet. Flatten each portion slightly into a cookie shape.
Bake. Bake for 12–15 minutes, until the cookies are set and lightly golden around the edges. Set aside to cool slightly before serving.
Make the smoothie while the cookies bake. Add the milk, vanilla protein powder, instant coffee, bananas, almond butter, and date syrup to a blender. Add ice cubes if desired. Blend until smooth and creamy.
Prepare the chamomile tea. Bring the water to a boil then remove from the heat. Steep the chamomile tea bags in water for 5 minutes, or according to the tea's instructions.
Serve the cookies with the smoothie and chamomile tea.