Heat 1 tablespoon oil in medium saucepot over medium-high heat. Add couscous and toast until lightly golden brown, about 1-2 minutes. Add vegetable stock and bring to a boil. Cover pot and reduce heat to low. Continue to simmer for 10 minutes or until all of the liquid is evaporated. Turn off flames and let couscous sit for 5 minutes. Remove lid and fluff with a fork.
Meanwhile, heat 1 tablespoon oil in nonstick saute pan over medium heat. Add sliced halloumi and sear on both sides until browned. Remove from heat and set aside.
In the same pan, melt 1 tablespoon butter. Add sliced leeks and saute until caramelized, about 5 minutes. Add garlic, peas, cooked couscous, pesto, herbs de provence, red chili flakes, lemon juice, and lemon zest. Season with salt and pepper and stir to combine. Cook for 1 more minute.
Remove couscous from heat and assemble onto plates. Top with halloumi and poached egg and drizzle extra pesto on top. Garnish with toasted almonds and fresh basil. Serve immediately.