Preparation:

Step 1: Preheat the Oven
Preheat your oven to 350°F (175°C). This ensures that your casserole will bake evenly and become wonderfully bubbly.

Step 2: Cook the Beef and Veggies
In a large skillet over medium heat, brown the ground beef until fully cooked, breaking it apart as it cooks. Drain any excess fat, then add the chopped onion and bell pepper. Sauté until the vegetables are tender, about 5 minutes.

Step 3: Add the Flavor
Stir in the drained diced tomatoes and taco seasoning. Mix well and let it simmer for another 2-3 minutes to allow the flavors to meld together.

Step 4: Prepare the Creamy Mixture
In a medium bowl, combine the sour cream, mayonnaise, and ranch dressing mix. Stir until smooth and set aside.

Step 5: Assemble the Casserole
In a greased 9×13-inch baking dish, spread half of the ground beef mixture at the bottom. Tear the refrigerated biscuits into pieces and place them on top of the beef mixture. Spoon the remaining beef mixture over the biscuits, followed by the creamy ranch mixture. Top it all off with shredded cheddar and Monterey Jack cheeses, and sprinkle sliced jalapeños on top if you like a bit of heat.

Step 6: Bake
Bake the casserole in the preheated oven for about 30-35 minutes, or until the biscuits are golden brown and the cheese is bubbly and melted. Let it cool for a few minutes before serving.