Before starting, preheat the oven to 425°F. Wash and dry all produce. Peel, then cut potatoes into 1-inch pieces. Add potatoes, 2 tsp salt and enough water to cover (by approx. 1 inch) to a large pot (use same for 4 ppl). Cover and bring to a boil over high heat. Once boiling, reduce heat to medium-high. Simmer uncovered until fork-tender, 10-12 min. Drain and return potatoes to the same pot, off heat. Mash 2 tbsp butter (dbl for 4 ppl) into potatoes until creamy. Season with salt and pepper, to taste.

Meanwhile, strip 2 tsp thyme leaves (dbl for 4 ppl) from stems, then finely chop. Heat a large non-stick pan over medium-high heat. When hot, add 1 tbsp butter (dbl for 4 ppl), then mirepoix. Cook, stirring occasionally, until veggies soften slightly, 1-2 min. Season with salt and pepper. Add bison to the pan with mirepoix. Cook, breaking up bison into smaller pieces, until no pink remains, 4-5 min.** Season with salt and pepper.

Add peas, half the thyme, tomato sauce base and 1/2 tsp vinegar (dbl for 4 ppl) to the pan with bison and mirepoix. Cook, stirring often, until fragrant, 1 min. Sprinkle Gravy Spice Blend over top. Cook, stirring constantly, until combined, 30 sec. Add broth concentrate and 3/4 cup water (dbl for 4 ppl). Bring to a simmer. Once simmering, cook, stirring often, until sauce thickens slightly, 1-2 min. Season with salt and pepper, to taste.

Transfer bison filling to an 8x8-inch baking dish (9x13 for 4 ppl). Top filling with mashed potatoes, then spread into an even layer. Sprinkle cheese evenly over top. Sprinkle with as much remaining thyme as desired. Bake in the middle of the oven, until mixture is bubbling around the sides, 14-16 min.

Meanwhile, halve grapes. Add remaining vinegar, 1/8 tsp sugar and 1 1/2 tbsp oil (dbl both for 4 ppl) to a large bowl. Season with salt and pepper, then whisk to combine. When pie is almost done, add grapes and arugula and spinach mix to the bowl, then toss to combine.

Allow pie to rest for 3-5 min. Divide pie between plates. Serve salad alongside.