Somali cuisine is very similar to others in the Horn of Africa (e.g., Ethiopia, Eritrea). Consequently, many dishes tend to appear in most of these cuisines. My categorization per country is thus purely to satisfy the rules of my own game and might not represent our world most accurately.
This is a really popular snack throughout the Horn of Africa (but really across large parts of the world). The sambuusa is more commonly known as samosa in Indian subcontinental cuisines. Wikipedia has more on the fascinating history of this food.
I made a large batch of sambuusa for a new year's celebratory buffet with friends, roughly following a handful of recipes (My Somali Food, The Somali Kitchen, Demand Africa).
Naturally, I opted for a vegetarian filling. I used a nice mix of lentils that predominantly consisted of firmer and darker varieties such as Le Puy, Beluga, and green lentils. Boil them until done but still quite firm. Heat some olive oil and sauté onions, garlic, and hot pepper (I had some Jalapeños). Now we add our spices. This is the stage that distinguishes the Eastern African way of preparing this snack. Our main spice is ground cardamom. Depending on your preference, add some cinnamon, cumin, or coriander. Include the drained lentils and cook until the mixture is sufficiently dried out. Throw in some cilantro leaves and let cool down.
The dough used to wrap sambuusa is supposedly also thinner than the one used for samosa. I went the easy route and used spring role pastry. Beware not to fill up a piece with too much filling; it wil go wrong. Be conservative and fold a lot of them. Heat some oil for frying and dunk in your sambuusas for three to four minutes. The fat will cool down but that is fine. We do not want to burn the outside too quickly anyway. Make sure the sambuusas are properly sealed and don't tear open, otherwise they will fill up with oil and become too greasy.
Serve them hot, at room temperature, or anywhere in between. Goes really well with a fresh and acidic chutney that compliments the earthiness of the lentil filling. I made a mint chutney with lemon, cilantro, onion, garlic, Jalapeño, and salt.