Preheat the oven to 390℉/180℃ Fan. Line a 2lb loaf tin with parchment/baking paper.
In a large bowl/bowl of a stand mixer, add all the cake ingredients and combine until smooth. If very stiff, add a little more milk. Set aside while you make the frangipane.
Make the frangipane: Combine the ground almonds, butter, egg, sugar, milk and almond extract to form a paste. Do this either with a spatula or with an electric mixer.
In the loaf tin, pour half the cake batter, then dollop some of the frangipane throughout. Swirl the frangipane into the batter. Add most of the remaining batter and swirl the rest of the frangipane throughout. Finally, pour over the last of the batter.
Bake 40-45 minutes, keeping an eye on it for if the top starts to look too dark. If the top gets dark while the middle is still not cooked, cover with aluminium foil until a skewer inserted comes out clean.
Once baked, remove and let cool.
Once cool, mix together the glaze and pour it over the cake while it is still in the pan. Scatter over slivered almonds and let set (either at room temperature or in the fridge) before slicing and serving!
