Whisk together the gin, Port, red wine, thyme, and juniper berries in a medium shallow baking dish. Add the venison and turn to coat. Marinate at room temperature for 20 minutes.
Remove from marinade and pat dry. Heat olive oil in a large saute pan over high heat. Season the venison with salt and pepper and cook on 1 side until golden brown, about 3 to 4 minutes. Turn over, reduce heat to medium and continue cooking for 3 to 4 minutes.
Plate with the Sweet Potato-Toasted Pine Nut Polenta, drizzled with the Crushed Blackberry-Ancho Chile Sauce.
Sweet Potato-Toasted Pine Nut Polenta:
Brush a little oil on a baking sheet and set aside. Heat 1 tablespoon of olive oil in a medium saucepan over medium heat. Add the onions and garlic and cook until soft. Add stock or water plus salt, increase heat to high and bring to a boil. Slowly whisk in the cornmeal with a wire whisk.
Once all of the cornmeal is whisked in turn the heat to low and continue cooking, mixing with a wooden spoon, until the mixture begins to pull away from the sides of the pan. Stir in the mashed sweet potato and butter and mix until combined. Stir the pine nuts into the mixture, season with salt and pepper and pour the mixture into the prepared baking sheet. Cover the top with plastic wrap and refrigerate until firm and chilled.
Remove from the refrigerator and cut into triangles, circles, or squares. Heat oil in a large saute pan, season the polenta slices with salt and pepper, and saute on both sides until golden brown.
Crushed Blackberry-Ancho Chile Sauce:
Melt the butter in a medium non-reactive saucepan over medium heat. Cook the celery, carrot, and onions until soft. Add the peppercorns, port, red wine, cranberry juice, ancho puree, brown sugar, and stock and cook over high heat, stirring occasionally, until reduced by half. Strain into a clean pot, add the blackberries, and cook over medium heat until the blackberries are soft, using the back of a fork, gently crush the blackberries. Season with salt, to taste.
Combine the ancho and water in a small bowl and let stand 1 hour. Drain well, reserving the soaking liquid. Remove the seeds and stems and puree in a food processor with the garlic, cilantro, and about 1/2 cup of the liquid, or more if needed.