veggie mac and cheese with popcorn topping

Ingredients For veggie mac and cheese with popcorn topping

• 2 c

  pasta
• 4 Tbsp

  unsalted butter, divided
• 1 c

  finely chopped onion
• 1 c

  shredded carrots
• 1 md

  yellow squash, halved lenthwise and thinlly sliced
• 2

  plum tomatoes, cored and coarsely chopped
• 3 c

  shredded extra-sharp cheddar, divided
• 1/2 c

  sour cream
• 1/2 c

  whole milk
• 2 lg

  eggs
• 1 tsp

  kosher salt
• 1/2 tsp

  black pepper
• 2 c

  cheese popcorn, lightly crushed