Preheat oven to 356F.
In a mixing bowl, mix with the tips of your fingers the flour, almond powder, butter and sugar until it forms small clumps (sand-like texture). Refrigerate while preparing the filling.
Peel and chop rhubarb in about 1-inch pieces. Cover with the sugar. Keep aside for about 30 minutes (it will help remove some of the acidity). Chop strawberries and add to the rhubarb. Add the rose water here if you want.
Toss the fruits in the baking dish of your choice (you can make a big one or individual portions) and avoid adding all the juice (strawberries will give away more juice while baking).
Cover the fruits with the crumble.
Bake for 25 to 30 min. Best eaten warm out of the oven.
For extra yumminess, add a spoon of crème fraiche on top of the crumble right before serving.