Preheat oven to 350 degrees. To a mixing bowl, add the fresh or frozen raspberries, granular sugar substitute, corn starch, lemon juice and lemon zest. Stir to coat the raspberries.
To a separate bowl, add the oats, almond flour, Swerve brown sugar, baking soda and salt. Stir together with a fork to break apart the brown sugar. Pour in the melted butter and stir to make a crumbly, gravel-like consistency.
Sprinkle the crumble over the top of the raspberry mixture. Place in 350 degree oven and bake for 22-25 minutes or until crumble is golden brown.
Remove from oven and let cool for 10 minutes before serving. Great served warm with vanilla ice cream.