Thermos Queso Dip
When we tested it, I swear, this stuff stayed warm and pliable in a preheated thermos for four hours.  It just needed a very quick stir and it was ready for dipping!
FOR THE VEGGIE PUREE:
1/2 cup thinly sliced (1/4 inch) carrots
1/2 cup water or chicken stock
Boil the carrots in the water or chicken stock until very tender (I confess I did this one in my microwave for convenience — it took about 7 minutes).  Use a blender, food processor, or immersion blender to puree until smooth.
FOR THE QUESO BASE:
2 tablespoons unsalted butter
2 tablespoons flour
1 cup milk
3/4 cup chicken stock
Veggie Puree (recipe above)
1 1/2 cups shredded extra-sharp cheddar cheese
2 slices (about 2 oz.) muenster cheese
1 tsp. salt
pinch black pepper
1/2-3/4 cup salsa, any brand you like

In a large saucepan over medium heat, melt the butter and whisk in the flour until it forms a paste.  Cook, stirring constantly, for 2-3 minutes.  Slowly pour in the milk and chicken stock, whisking, until all the liquid is incorporated and there are no lumps.  Turn up the heat to medium-high and let the sauce bubble for about 5 minutes, until it’s thick enough to coat the back of a spoon.
Turn the heat to medium-low, add the veggie puree and cheeses to the sauce, and stir until the cheeses are melted and everything is combined.  Season with salt and pepper.  Add 1/2 cup of salsa and mix thoroughly.  Taste and add more salsa if you prefer.  Serve immediately with chips, or pour into a preheated Thermos and pack in a school lunch.
Queso variations: Stir in 1 cup of leftover chili, 10 oz. of chopped frozen spinach (squeezed dry), or 1 cup of black beans cooked with 2 tablespoons of chopped onion, 1 tsp. each cumin and chili powder, and 1/2 cup crushed tomatoes.