1. Prepare the Lentils:
Place your dry lentils in a fine-mesh sieve. Rinse them thoroughly under cold running water. Pick through them quickly to remove any small stones or debris that may have found their way into the bag. Set aside.

2. Sauté the Aromatics:
In a large pot or Dutch oven, heat the olive oil over medium heat. Once the oil is shimmering, add the finely chopped yellow onion and bell pepper. Sauté for 5-7 minutes, stirring occasionally, until the onions become translucent and have softened. Add the minced garlic and cook for another minute until fragrant. Be careful not to let the garlic burn.

3. Bloom the Spices:
Add the chili powder, ground cumin, smoked paprika, and dried oregano directly to the pot with the sautéed vegetables. Stir constantly for about 30-45 seconds. This step toasts the spices, releasing their essential oils and creating a much deeper, more robust flavor profile. Your kitchen should start to smell amazing!

4. Combine and Simmer:
Pour the rinsed lentils, vegetable broth, and tomato sauce into the pot. Stir everything together, making sure to scrape up any browned bits from the bottom of the pot (this is where a lot of flavor lives). Bring the mixture to a boil.

5. Cook the Lentils:
Once the mixture is boiling, reduce the heat to low, cover the pot, and let it simmer for 30-35 minutes. Stir occasionally to prevent the lentils from sticking to the bottom. The lentils are done when they are tender but still hold their shape. Most of the liquid should be absorbed, leaving you with a thick, hearty filling. If the mixture looks too dry before the lentils are cooked, add a splash more vegetable broth or water. If it looks too wet at the end, simply let it simmer uncovered for a few more minutes to thicken up.

6. Finish the Filling:
Turn off the heat. Stir in the gluten-free tamari, salt, black pepper, and the optional maple syrup. The tamari adds a crucial umami depth, and the maple syrup balances the acidity of the tomato sauce. Taste the filling and adjust the seasoning as needed. You may want more salt, a little more chili powder for heat, or a squeeze of lime juice for brightness.

7. Assemble Your Tacos:
Warm your gluten-free corn tortillas or hard taco shells according to the package directions. Spoon a generous amount of the warm lentil filling into each shell and serve immediately with your favorite toppings.