In a mixing bowl, stir together the cream cheese, garlic, lemon juice, nutritional yeast, parsley, half of the cheddar cheese, half of the breadcrumbs, salt and pepper.
Start by slicing each jalapeño in half lengthwise. You can leave the stem attached, as it provides a nice handle for the poppers. Then, remove the seeds and the white membrane inside the peppers.
Fill each pepper with cream cheese filling. Sprinkle with remaining cheddar cheese and breadcrumbs. For extra crispness, you can spray the filled peppers with cooking spray (or drizzle with olive oil) before baking.
Bake for 15-20 minutes, until the peppers are soft and the top is golden brown