Begin by melting 3 tbsp of butter in a large pan over medium heat. Once the butter is foaming, add 2 crushed garlic cloves and cook gently while stirring occasionally for 1–2 minutes until the garlic is soft but not colored.
This indispensable first step builds the aromatic foundation for the dish. Next, add 2 yams (total weight 2 lb/1 kg), trimmed but unpeeled and cubed, to the pan. Toss the yams over medium to high heat for 1–2 minutes to coat them evenly with the butter and allow them to begin softening slightly.
Stir in 1 tsp mild chili powder, ¼ tsp paprika, and ¼ tsp ground cinnamon, mixing thoroughly to distribute the spices evenly throughout the pan.
Pour in 1 × 7 oz (200g) can of chopped tomatoes and cook the mixture over medium heat for 1–2 minutes, allowing the spices to bloom and the tomatoes to incorporate with the other ingredients.
Season with salt to taste, then cover the pan and reduce the heat to a gentle simmer.
Allow the yams to cook for 15–20 minutes until they are completely tender. During cooking, turn the yams occasionally with an offset spatula to guarantee even cooking, but avoid stirring vigorously as this will break them apart and compromise the dish's presentation.
Once the yams are fork-tender and the sauce has thickened slightly, transfer to serving dishes and top each portion with a dollop of plain yogurt and a sprinkle of freshly chopped parsley.
