Stir together semolina, baking powder, 2 cups of sugar, and chopped almonds until evenly blended. Stir in yogurt, vegetable oil, and rose water until a soft dough forms. Cover bowl with plastic wrap, and allow to rest at room temperature for 30 minutes.
Preheat oven to 350 degrees F (175 degrees C). Press the dough into a 9x9 inch square baking dish, and smooth the top. Score the top of the dough to create 25 squares, then top each square with an almond half.
Bake in preheated oven until the top has puffed and turned golden brown, about 20 minutes. The harisseh is done when the top is golden, and the center has firmed. When done, remove from the oven, and allow to cool in the pan for 20 minutes.
While the harisseh is cooling, pour water and 2 cups of sugar into a saucepan. Bring to a simmer, and cook for 5 minutes. Stir in 1 teaspoon of rose water, and lemon juice, then remove from the heat.
To serve, cut the warm harisseh into 25 squares, and place onto a large serving platter; pour the rose water syrup over, making sure all of the pieces are moist.
