Preheat the oven to 350 degrees F.

In a large mixing bowl, combine the berries, Grand Marnier, granulated sugar, cornstarch, and lemon juice. Toss to mix and let sit for 15 minutes.

Grease six 6-ounce ramekins (** see Note 1) with one tablespoon of the butter. Divide the berry mixture equally among the ramekins.

In a food processor, combine the butter, brown sugar, flour, oats, cinnamon, and salt. Pulse until the mixture resembles crumbs.

Place a heaping 1/4 cup of topping on top of the berries in each ramekin. Put the ramekins on a baking sheet and bake until crumbs are golden brown and crisp, and juices are bubbling around the edges of the ramekins, 30 to 40 minutes. Remove from the oven and let cool slightly. Top each cobbler with a scoop of ice cream, if you wish, to serve.

Note 1:  The cobbler may also be baked in one shallow 1 1/2- to 2-quart baking dish. If you opt to do so, cut the oven temperature down to 325 degrees F and know that the cooking time is likely to be a bit longer.

Note 2:  You will have a small amount of crumble topping leftover -- enough for about 4 more ramekins. You can either increase the fruit amounts proportionally and make additional cobblers, or store the crumb topping in an airtight container in the freezer and use it for future crisps and cobblers.