Chop the walnuts into small pieces and set them aside.

In a bowl, mix the dry ingredients: almond flour, baking soda, chia seeds, pumpkin seeds, and chopped walnuts.

In a separate bowl, whisk the eggs. Add coconut oil or melted butter and whisk until smooth. Then, mix in maple syrup, lemon zest, and lemon juice.

Combine the wet mixture with the dry ingredients and stir gently until fully mixed.

Carefully add the blueberries and mix slowly to keep them whole.

Preheat the oven to 350°F (175°C).

Prepare the baking sheet by greasing it.

Pour the batter onto the baking sheet and bake for about 45 minutes, or until the top is golden brown.

Let the cake cool in the fridge for at least 6 hours or overnight before serving.

Serve it with hot tea.