Prep the oven and pan. Heat the oven to 400°F (200°C). Line a baking sheet or shallow baking dish with parchment for easier cleanup.
Hollow the zucchini. Slice each zucchini lengthwise. Use a spoon to scoop out the seeds and some flesh, leaving a 1/4-inch shell.
Don’t toss the flesh—chop about 1/2 cup of it to add to the filling for extra moisture.
Soften the shells. Brush zucchini boats with olive oil and a pinch of salt. Place cut-side up on the pan and bake for 8–10 minutes to soften slightly. This helps them bake evenly once stuffed.
Mix the buffalo base. In a bowl, stir together cream cheese, sour cream, melted butter, buffalo sauce, garlic powder, onion powder, smoked paprika, pepper, and a pinch of salt.
Mix until smooth and creamy.
Add chicken and zucchini bits. Fold in the shredded chicken, the chopped zucchini flesh, and half the green onions. Taste and adjust heat with more buffalo sauce if you like it spicier.
Stuff the boats. Spoon the buffalo chicken mixture evenly into each pre-baked zucchini shell, mounding slightly.
Top with cheese. Sprinkle mozzarella (or Monterey Jack) over the stuffed zucchini. Add crumbled blue cheese if using.
Bake. Return to the oven and bake for 12–15 minutes, until the zucchini is tender and the cheese is melted and lightly golden.
Finish and serve. Let rest 5 minutes.
Drizzle with ranch or blue cheese dressing, sprinkle with remaining green onions and parsley or celery leaves. Serve warm.