Preheat your oven to 375°F (190°C) and line a baking sheet with parchment paper or aluminum foil for easy cleanup.
Prep the jalapeños: Put on disposable gloves to protect your hands. Cut each jalapeño in half lengthwise. Using a spoon, remove the seeds and membranes. (Pro tip: The more membranes you remove, the milder they'll be.)
Cook the sausage: In a large skillet over medium heat, brown the sausage, breaking it into small crumbles as it cooks (about 5-7 minutes). Drain excess grease if necessary.
Make the filling: In a mixing bowl, combine the cooked sausage, softened cream cheese, cheddar cheese, Parmesan, minced garlic, green onions, smoked paprika, and black pepper. Mix thoroughly until well-combined.
Stuff the peppers: Spoon the filling into each jalapeño half, mounding slightly (they'll shrink a bit during baking). Place stuffed jalapeños on the prepared baking sheet.
Bake to perfection: Place the baking sheet in the oven and bake for 20-25 minutes, or until the jalapeños are tender and the filling is golden and bubbly.
Optional broil: For an extra golden top, broil for 1-2 minutes at the end of baking time (watch carefully to prevent burning).
Cool slightly: Allow the stuffed jalapeños to cool for 5 minutes before serving—that filling gets nuclear hot!
Garnish and serve: Add any optional toppings like extra cheese, bacon bits, or fresh herbs before serving.