FOR THE ICE CREAM:

1. Place the mastiha tears in a small dish and freeze for 15 minutes
2. Crush the mastiha with a mortar and pestle, or wrap them in a small piece of parchment & crush them with a rolling pin
3. In a saucepan over medium heat, add the 1/3 cup water and crushed mastiha tears. Simmer for about 5 minutes and then strain the mastiha water through a fine sieve into a small dish
4. In a medium bowl, stir together condensed milk, rosewater & mastiha water
5. With a standing mixer or hand mixer, whip cream on medium high until soft peaks form.
6. Whisk one third of whipped cream into the sweetened condensed milk mixture.
7. Fold the remaining whipped cream into sweetened condensed milk mixture. Pour mixture into a freezable container ( a loaf pan works nicely ) and freeze until ice cream is firm, 6 hours ( or, covered, for up to 1 week )

FOR THE CRUMBLE:

1. Preheat oven to 175°C (350°F).
2. Add sugar, almond flour, salt, oats, mahlepi and softened butter to a bowl. Using your hands, mix together until crumbly.
3. Spread on a baking sheet lined with parchment paper and bake for 8-10 minutes. Let crumbles cool, then serve with ice cream.
4. Garnish with dried rose petals if desired.