Preheat the oven to 425°F and line a sheet pan with foil.
Take each jalapeño and cut in half lengthwise, removing the stem and seeds. Remove the boudin sausage from the casing. Cut each slice of bacon in half.
To assemble, evenly spoon some of the sausage into each jalapeño half. (I don’t measure, but it’s probably about a couple of teaspoons per half.) Take a piece of bacon and wrap it around the jalapeño, with the ends of the bacon ending on the underside of the pepper.
For the seasoning, stir together the cayenne, chili powder, garlic powder, cumin, oregano, and salt. (If you already have a pre-mixed Cajun seasoning, you may use this instead.)
Place the jalapeños sausage-side up on the sheet pan, spaced about 1/2-inch apart. Sprinkle the jalapeños evenly with the seasoning.
Cook uncovered for 25-30 minutes or until the bacon is cooked and the sausage is browned. Serve warm with ranch dressing.