Cauliflower Lentil Sloppy Joes

Ingredients (21)

• 1 cup red lentils
• 2 cups water
• 1  small head cauliflower
• 2  tablespoons olive oil
• 1  small yellow onion
• 1/2 large red bell pepper
• 1 celery stick
• 1 carrot
• 2 cloves garlic
• 2  15 oz cans crushed tomatoes 
• 1 8 oz can tomato sauce
• 1/4 cup ketchup
• 2 tablespoons  worcestershire sauce
• 2 tablespoons red wine vinegar
• 2 tablespoons brown sugar
• 1 1/2 teaspoons chili powder
• 1 teaspoon ground mustard
• 1/2 teaspoon smoked paprika
• 1/2 teaspoon ground cumin
• Kosher salt and black pepper
• 4 whole wheat hamburger buns