Preheat the Oven:
Preheat your oven to 350°F (175°C). Grease a baking dish (8×8 inch or similar size) with oil or
butter. 

Prepare the Berry Filling:
In a large bowl, combine the mixed berries, granulated sugar, cornstarch, lemon juice, and vanilla extract. Toss gently to coat the berries evenly with the sugar and cornstarch mixture. 

Make the Crumble Topping:
In another bowl, mix together the rolled oats, all-purpose flour, brown sugar, ground cinnamon, and salt. Stir until well combined. Add the Bella Del Sol high oleic sunflower oil and mix until the mixture resembles coarse crumbs.

Assemble and Bake:
Spread the berry mixture evenly in the greased baking dish. Sprinkle the crumble topping evenly over the berries.

Bake:
Place the baking dish in the preheated oven and bake for 35-40 minutes, or until the berry filling is bubbly and the crumble topping is golden brown.

Serve:
Remove the pot from the oven and let it rest for a few minutes. Serve the roasted hare haunches with the stewed vegetables, garnished with fresh herbs like thyme or rosemary.