Place the cookies in a food processor and process them into fine crumbs. (Alternatively, put them in a freezer bag and crush them with a rolling pin).

Transfer the cookie crumbs to a bowl. Add the melted vegan butter and mix to combine. Then press the mixture into a 9-inch tart pan (or another pan with removable bottom). Place it in the freezer for 15 minutes (or in the refrigerator for 30 minutes) so the crust solidifies.

You could also pre-bake the crust (see notes below).

Pour the coconut milk into a saucepan. Stir in the agar until it has completely dissolved. Bring to a boil and cook for 1-2 minutes (or according to the package instructions), stirring constantly.

Turn off the heat and stir in the agave syrup (or sugar) and lime juice. Allow to cool briefly and pour onto the chilled crust. Place it in the refrigerator for about 1 hour until the top has set.

Pour the water into a small cup and stir in the spirulina powder to dissolve. Set aside.

Add the coconut milk to a saucepan. Stir in the agar until it has completely dissolved. Bring to a boil and cook for 1-2 minutes (or according to the package instructions), stirring constantly.

Turn off the heat and stir in the agave syrup (or sugar), vanilla extract, and the spirulina water. Carefully, pour it on the lime layer, then place back in the fridge for another 2 hours, or until firm.

Once the filling has set completely, carefully remove the tart by gently pressing against the removable bottom of your pan. Garnish with fresh blueberries, blackberries, and limes.