Coat a large baking sheet (or 2 standard sheets) with nonstick oil spray or parchment paper and set aside.
Remove the stems and seeds from the bell pepper and cut each into 4 quarters.
Lay the bell pepper "chips" on the prepared baking sheet(s) in a single layer with their insides facing up like a partial bowl that will hold the meat filling.
In a large frying pan, stir the ground beef until it's cooked through and crumbled.
Add the taco seasoning along with about 2/3 cup water and the cream cheese. Stir until it’s fully combined
Add the jalapeños, if using. Mix until well-combined and heated through.
Spoon the seasoned ground beef over the bell pepper pieces.
Sprinkle on the cheese and bake for about 10 minutes, until the cheese is melted.
Remove the baking sheet from the oven and, if desired, top with the salsa, pipe on swirls of the yogurt or sour cream, and garnish with scallions or cilantro.