Preheat the oven to 375°. In a pot of boiling, salted water, cook the couscous until tender, about 5 minutes. Drain and let cool slightly.
Meanwhile, in a large skillet, heat 2 tbsp. butter over medium heat. Add the cumin and cook, stirring, for 1 minute. Add the onions, season with salt and pepper and cook, stirring occasionally, until crisp-tender, about 5 minutes. Remove the pan from the heat and let the onions cool slightly. Transfer one-third of the onions to a food processor along with the remaining 1 tbsp. butter.
Add the couscous to the skillet with the remaining onions; stir to combine. Stir in the meatloaf mix, raisins and 1/2 tsp. each salt and pepper until just combined. Fill the bell pepper quarters with the meat mixture and transfer to a baking dish. Cover with foil and bake for 15 minutes.
Meanwhile, add the roasted peppers and 1/8 tsp. each salt and pepper to the onions in the food processor; puree until smooth. Top the stuffed peppers with the red pepper puree and bake again, uncovered, until the bell peppers are slightly tender, about 20 minutes. Top with the almonds and serve.