Wash and dry the fresh produce.
Peel and medium dice potatoes; place in a medium saucepan and cover with hot water (from the tap). Cover and bring to a boil over high heat; once boiling, reduce to a simmer and cook until soft, 10-12 minutes.
Meanwhile, preheat a skillet over medium-high heat. Once hot, add butter and swirl to coat the bottom. Add pork, then cover and cook until seared on one side, 8-9 minutes. Flip and cook, still covered, an additional 8-9 minutes, until internal product temperature reaches 145°F on a meat thermometer. Remove to a plate and set aside to rest. (Reserve skillet for later use.)
While the pork is cooking, place broccoli and cauliflower in another medium saucepan; cover with hot water (from the tap), and bring to a boil over high heat. Once boiling reduce heat to medium and cook until veggies are fork-tender, 3-4 minutes. Drain and return to the pan, then add butter and spices. Stir to coat, cover to keep warm, and set aside.
When the potatoes are done, drain in a colander and return to the pan. Add milk, butter, salt, and pepper, then using a potato masher, mash until smooth. Cover and set aside.
When the pork is done, wipe the skillet clean with paper towels and return to medium-high heat. Add more butter and swirl to coat the bottom. Add jalapeño peppers and cook, turning occasionally, until charred and fork-tender, about 3 minutes. Remove from heat.
Thinly slice pork.
Wash, dry, and shave cilantro leaves off the stems; discard stems and mince the leaves.
To serve, divide mashed potatoes, broccoli, cauliflower, jalapeño, and pork between plates. Sprinkle with cilantro and enjoy!