Preheat the oven to 350°F with a rack in the center. Spray a 13x9-inch glass baking dish.

Place the biscuits in the dish in a single layer and press them into the pan, joining them together and pressing the dough halfway up the sides. Set the dish on a baking sheet and bake 12 to 15 minutes, checking every few minutes after 12, until the dough is very light brown where the edges are just starting to color. Leave the oven on.

While the crust bakes, brown the ground beef in a large skillet until no longer pink (160°F) and drain it. Add the taco seasoning and the water listed on the packet and cook according to the packet directions. Transfer the meat to a bowl and wipe out the pan.

In a separate bowl, stir together the sour cream, mayonnaise, 4 ounces of the cheddar and half of the onion.

Sauté the remaining onion and the bell pepper in the same pan until slightly tender.

On the baked crust, layer the taco meat, tomato slices, pepper and onion mixture, jalapeños and the sour cream mixture, then sprinkle with the remaining 4 ounces of cheddar. Bake uncovered 30 to 40 minutes, until the edges of the dough are lightly browned, the cheese is melted and the center reaches 165°F.