In a large skillet over medium-high heat, brown the ground beef. Drain off any excess grease.

Add the chopped onion to the skillet and cook until softened, about 5 minutes. Stir in the minced garlic and cook for another minute until fragrant.

Stir in the undrained diced tomatoes, rinsed black beans, drained corn, taco seasoning, salsa, and optional jalapeños. Bring to a simmer and cook for 5-7 minutes, allowing flavors to meld.

Reduce heat to low. Add the softened cream cheese cubes to the skillet and stir until melted and the dip is creamy. Season with salt and pepper to taste.

Stir in the shredded cheddar and Monterey Jack cheeses until fully melted and combined. The dip should be thick and gooey.

Transfer the dip to a serving dish. Top with a dollop of sour cream and a sprinkle of extra cheese or chopped jalapeños if desired.

Serve hot with tortilla chips, crackers, or vegetable sticks.