Preheat oven to 400 F. Meanwhile, peel and dice butternut squash into ½ in - 1 in cubes. Coat with olive oil, salt and pepper, and roast for 20 mins. Flip squash, and roast for another 20 mins, or until lightly golden and soft.
Slice jalapeños into thin discs, and put in a jar. Add enough seasoned rice vinegar until it almost covers all of the jalapeños. Set aside for at least 1 hour. If you're going for less spicy, slice bell pepper into slivers, discarding the seeds and stem.
Prep toppings. Thinly dice red onion and chili peppers. For non spicy peeps - slice ½ of the red onion into slivers, and sauté with sliced bell pepper until soft, and a little brown.
For guac: smash avocado, add salt, pepper and red onion to taste. For 1 small avocado, I use a pinch of salt, 1 Tbsp (ish) red onion, and ¼ lime, juiced.
Once butternut squash is ready, mash in a bowl with juice of ½ lime until smooth-ish.
On a nonstick skillet over medium heat, add tortilla, and carefully smear on a layer of butternut squash. Add whatever toppings you like. I used my pickled jalapeños, red onion, and black beans. Non spicy - add sautéed veggies.
After 2-3 mins, check the bottom of the tortilla by lifting with a spatula. If there are some brown spots, put another tortilla on top, and carefully flip. It's ok if some stuff falls out - that's what I call a "chef snack." Let cook for another 2-3 mins, then use slide off pan and onto a plate. Slice, and serve!