Preheat oven to 375º F.

Line large baking sheet with parchment paper. Set aside.

Cut spaghetti squash in half lengthwise. Remove seeds and membrane.

Place spaghetti squash, cut side up, on baking sheet. Evenly drizzle with 1 Tbsp. oil. Season with salt and pepper. Place cut side down.

Bake for 40 to 45 minutes, or until tender.

While spaghetti squash is baking, make coleslaw by combining green and red cabbage, mayonnaise, mustard, celery seed (if desired), and white pepper in a medium bowl; mix well. Refrigerate, covered, until ready to use.

Heat remaining 1 Tbsp. oil in large nonstick skillet over medium-high heat.

Add onion; cook, stirring frequently, for 4 to 5 minutes, or until onion is translucent.

Add garlic powder, cumin, paprika, and red pepper flakes (if desired); cook, stirring constantly, for 2 minutes.

Add broth; cook, stirring frequently, for 1 minute. Remove from heat. Set aside.

Scrape spaghetti squash flesh into stringy noodles. Add to skillet; cook, over medium-high heat, stirring frequently, for 1 to 2 minutes, or until broth is absorbed.

Add barbecue sauce; cook, stirring constantly, for 3 to 4 minutes, or until well coated and heated through.

Evenly top each bottom roll with spaghetti squash mixture, coleslaw, 2 pickles, and top roll; serve immediately.