In a large bowl, mix together coarse and fine semolina, and pour on the melted butter. Stir to thoroughly coat the semolina with the butter, you may find it easier to work this in with your hands a little. Cover the bowl with plastic wrap, and set aside to rest for minimum 1 hour but preferably 4 hours-overnight at room temperature. This will stop the semolina from being grainy and crumbly, it'll become fluffier as it absorbs the liquid.
Preheat oven to 350 F (180C). Once the semolina has soaked up the butter, add the baking powder, baking soda, and salt, and stir to combine. Set aside.
In another medium bowl, whisk together the yogurt, the sugar, and the vanilla extract until smooth and combined.
Add the yogurt mixture to the semolina, and use a spatula to mix well, smoothing out any lumps.
Brush the tahini onto the base of a 13x9 pan (or grease with pan spray or butter and flour). Pour the semolina mixture onto the base and smooth out with a spatula.
Using a sharp knife, cut little diamond shapes into the bars (see the video for a demonstration). Top each diamond with a blanched almond, pressing down slightly to get them to stick.
Bake in the middle rack of the oven for 35-45 minutes until deep golden brown. If you can, lift up a small piece on the edge to make sure the namoura is cooked through on the base as well.
As soon as the namoura is out of the oven, pour the sugar syrup all over the hot namoura. You can choose not to use all of the sugar syrup you prepared if you want it a little less sweeter, but I use the whole thing. It will seem like a lot but it'll soak into the namoura as it sits, giving it that signature texture.
Let the namoura sit for at least an hour at room temperature to soak up the syrup before cutting into bars along the diagonal lines you scored. Enjoy!