In a large skillet add hamburger and onion, cook over medium-high heat until meat is thoroughly cooked and onion is translucent. Add in diced tomatoes, kidney beans, tomato paste, salsa, and chili powder. Cook for 3-5 minutes, set aside.
Preheat oven to 400ºF. Spray mini muffin pan with cooking spray if making bites.
Prepare KRAFT Deluxe Macaroni & Cheese Dinner in large saucepan as directed on package.
Once noodles are done, pour noodles into the skillet with the meat and add in cheese sauce, stir together until well combined. *At this point if you want to leave it as a skillet bake, top with cheese then serve when it melts.
In a small bowl whisk egg, stir into pasta until combined.
Spoon mixture into mini muffin pan. To make this easy I used my cookie dough scooper which made it less messy. Depending on how much you add to each muffin cup, you should get 32-36 muffin cups filled, it is about 2 tablespoons in each muffin cup.
Top with a pinch of KRAFT Finely Shredded Cheddar Cheese.
Place in the oven and bake for 10 to 12 minutes or until golden brown.
Let it cool for a few minutes, then remove from pan onto serving plate.
Garnish with a dash of sour cream and top with green onions if desired. Serve and enjoy!