Almond Crumble Topping:
¾ cup slivered almonds, toasted
1 cup all-purpose flour
⅓ cup sugar
¼ teaspoon kosher salt
1 stick butter
Crumble:
6 cups rhubarb, cut into 1/2-inch pieces
1 cup roughly chopped strawberries
½ cup sugar
2 tablespoons cornstarch
zest and juice of ½ lemon