Keto Rhubarb Berry Crumble

Name: Keto Rhubarb Berry Crumble
Prep time: 10 min
Cook time: 40 min
Total time: 50 min
Cuisine: European, British
Ingredients: 500 gms rhubarb (trimmed and diced into 1 "/ 2.5 cm chunks); 500 gms mixed berries, raspberries or strawberries (fresh or frozen); ¼ cup monk fruit ((1:1 to sugar), erythritol, xylitol or alternate sweetener - see notes); Finely grated zest of 1 lemon and a squeeze of lemon juice; 80 gms butter; ⅓ cup erythritol (, xylitol or alternate sweetener- see notes); 1 cup almond meal; 1 tablespoon coconut flour (optional); ¾ cup desiccated coconut; ⅓ cup flaked or slivered almonds; A pinch of salt