Spicy Lentil Quinoa Curry

Name: Spicy Lentil Quinoa Curry
Ingredients: 1 tablespoon olive oil; 1 cup diced onion; 1 cup chopped mushrooms; 0.5 cup chopped carrots; 3 cloves garlic, minced; 4 cups vegetable broth; 1 cup water; 1 cup dry green lentils; 0.5 cup quinoa; 2 tablespoons tomato paste; 2 tablespoons curry powder; 1 tablespoon ground red chile pepper; 1 tablespoon ground cumin; 1 tablespoon ground ginger; 1 teaspoon cayenne pepper; 1 teaspoon garam masala (Indian spice blend); 1 teaspoon ground turmeric; 1 teaspoon salt, or to taste; 1 dash ground black pepper, or to taste; 0.25 cup milk; 1 tablespoon butter