Preheat your grill or a broiler. Place the poblano peppers on the grill or under the broiler, turning occasionally until charred and blackened all over, about 10-15 minutes. Once charred, place them in a bowl covered with plastic wrap to steam for about 10 minutes. This will make peeling easier.

In a dry skillet over medium heat, add the coriander seeds. Toast them for about 2-3 minutes, stirring frequently, until fragrant. Remove from heat and let cool. Once cooled, crush the seeds using a mortar and pestle or a spice grinder.

Pat the bison tenderloin dry with paper towels. Rub the tenderloin with olive oil, then season generously with salt, pepper, and the crushed coriander seeds, ensuring an even coating.

In a hot skillet or on the grill, sear the bison tenderloin for about 4-5 minutes on each side for medium-rare (adjust cooking time based on thickness and desired doneness). Use a meat thermometer to ensure it reaches an internal temperature of 130°F (54°C). Once cooked, remove from heat and let rest for 10 minutes before slicing.

While the bison is resting, heat a tablespoon of olive oil in a saucepan over medium heat. Add the chopped onion and sauté until translucent, about 5 minutes. Add the minced garlic and cook for an additional minute until fragrant. Stir in the smoked tomatoes, broth, balsamic vinegar, and smoked paprika. Bring to a simmer and cook for about 10 minutes, allowing the flavors to meld together. Use an immersion blender to puree the mixture until smooth. Adjust seasoning with salt and pepper.

Slice the bison tenderloin into medallions. Serve on a plate drizzled with the silky smoked tomato gravy. Garnish with chopped fresh cilantro and additional roasted poblano peppers if desired.