In a dry skillet over medium heat, toast sunflower seeds until fragrant. Remove from heat and set aside to cool for a minute. Place seeds and dates in a food processor with sea salt and pulse to chop until they are to your desired fineness (process a finer crust longer than a chunky one). Test the crust by spooning out a small amount of mixture and rolling it in your hands. If the ingredients hold together, your crust is perfect (if it’s too dry, add more dates, if it’s too wet add sunflower seeds).
Add crust mixture to a 7” spring-form pan (if you don’t have a spring-form pan, use a pie plate lined with plastic wrap), and press firmly, making sure that the edges are well packed and that the base is relatively even throughout.
Warm coconut oil and honey in a small saucepan on low heat until liquid. Add vanilla and whisk to combine.
In the most powerful food processor / blender you own, place all filling ingredients, except for one tablespoon of the lemon juice, and blend on high until very smooth (this make take a couple minutes so be patient).
Pour about ⅔ (just eyeball it, you can’t make a mistake!) of the mixture out onto the crust and smooth with a spatula. To the reserved filling, add the blueberries and cardamom, plus remaining tablespoon of lemon juice, blend on high until smooth. Pour onto the first layer of filling. Place in freezer until solid.
To serve, remove from freezer 30 minutes prior to eating. Place blueberries on top of the cake and decorate with edible flowers. Run a smooth, sharp knife under hot water and cut the cake into slices. Say thank you and enjoy. Store leftovers (without toppings) in the freezer for up to a couple months.