Thoroughly rinse the lentils. Place the lentils and 2 cups of water in a large pot and bring to a boil. Reduce heat to low and simmer for 35-40 minutes or until lentils absorb most of the water. Remove from heat and set aside.
While the lentils are cooking, mix ground flax seed and 1/3 cup water in a small bowl and set aside.
Prepare the glaze by mixing the tomato sauce, mustard, cider vinegar, soy sauce, and sriracha in a measuring cup.
Preheat oven to 350 degrees F. Prepare a 9 inch loaf pan by greasing it with a few drops of vegetable oil.
In a nonstick pan, dry sauté onion, bell pepper, carrots and jalapeño until onions are translucent and carrots soften a bit. Transfer to a large bowl, stir in spices and basil, and set aside.
Using a blender or food processor, blend 1/2 of lentils. Transfer to the bowl with the sauteed veggies, and stir in the remaining lentils along with the oat flour, and the flax seed and water mixture. Add salt and pepper, then adjust the seasonings to taste.
Spoon the mixture into the prepared loaf pan, pressing it evenly into the pan to fill any spaces. Smooth the top of the loaf, then spread the glaze over the top.
Bake loaf for 45 minutes. Remove from oven and cool for 5-10 minutes before slicing.
This loaf is delicious with a simple gravy. It also makes excellent leftovers and sandwiches.