Mix the chia seeds and the water and let it sit for 10-15 minutes until it turns into a gel.
Preheat oven to 200° C / 390°F. Place the hazelnuts on a baking sheet with baking paper and put them in the oven while it heats until they are roasted. Time depends on, which oven you have, so look closely. The nuts are done when they smell nice and have turned slightly golden brown.
Place roasted nuts, oats, sukrin gold (or coconut sugar), buckwheat flour, salt and cinnamon in a food processor. Pulse three times or so - just to mix it. Add in the cold coconut oil and applesauce and pulse to combine. Add in the maple syrup if needed – or a bit more apple sauce.
Press 2/3 of the dough into a pan and leave the rest in a bowl.
Wipe clan the food processor (no need for washing) and blend all the ingredients for the filing until completely smooth. Pour out into the filling in the pan.
Sprinkle on the rest of the filling and bake for approx. 20 minutes – or until the crumble is nice and brown.
Cut into squares and serve right away or store them in an airtight container in the fridge for up to 5 days – they make a great breakfast or evening snack.