Smoky Lentil Soup with Grown-Up Grilled Cheese Sandwiches

3 thick-cut bacon slices 

2 Tbs. olive oil 

1 small yellow onion, diced 

1 carrot, peeled and cut into 1/4-inch dice 

1 celery stalk, cut into 1/4-inch dice 

1 tsp. minced garlic 

1 Tbs. tomato paste 

1 tsp. smoked paprika 

1/4 cup canned diced tomatoes, drained 

3/4 cup Red Chief lentils, picked over and rinsed 

4 cups chicken broth 

Kosher salt and freshly ground pepper, to taste 

Sour cream for garnish 

Grown-up grilled cheese sandwiches for serving