Preheat the oven to 375°F and spray a baking sheet with cooking spray. Have the pan ready before assembling the pockets because warm filling can soften the refrigerated dough.
Heat 1 tablespoon avocado oil in a large skillet over medium-high heat. Add the onion and green bell pepper and cook for 2–3 minutes, until softened and the onion is translucent.
Move the vegetables to the side of the skillet and add the ground beef. Cook and crumble for 5–6 minutes, until no pink remains and the thickest portion reaches 160°F on an instant-read thermometer.
Stir in the taco seasoning and cook for 1–2 minutes. Add the beef broth, bring the mixture to a boil, then continue cooking until the broth has reduced and absorbed into the filling. Remove the skillet from the heat.
Open both tubes of crescent roll dough and unroll them on a large cutting board. Use the perforations to create 8 rectangles total, then pinch each diagonal seam closed on both sides. Arrange the rectangles on the prepared baking sheet before filling, allowing part of each rectangle to hang over the edge if needed for space.
Spoon 1/4 cup beef filling onto one side of each rectangle, then top each with 1 tablespoon cheddar cheese.
Fold the dough over the filling and firmly seal all 3 open edges. Bake for 9–12 minutes, until the pockets are golden brown.
Remove the pan from the oven. Divide all of the remaining cheddar evenly over the tops of the 8 pockets, then add sliced jalapeño, if using.
Return the pan to the oven and broil for 1 minute, watching closely, until the cheese melts.
Serve warm with your favorite taco toppings.