In a small bowl, whisk together the flour, baking powder, and salt. Set aside.
Add the sugar and orange zest to a medium sized mixing bowl. Use your hands to rub the orange zest into the sugar until the sugar is fully coated and slightly orange.
Add in the butter, and beat for 3-4 minutes or until the mixture is light and fluffy.
Use a rubber spatula to scrape down the sides of the bowl. Add in both eggs and the vanilla, then beat until well combined (~1 min.)
Add in half of the flour mixture, and mix by hand just until the flour is incorporated. Add in all of the buttermilk and mix until combined. Add in the rest of the flour, and lightly fold the mixture together just until all of the flour is incorporated.
Pour the cake batter into the prepared cake pan and smooth out the top. Gently spread the cranberry jam into an even layer over the cake batter. Top with the streusel, followed by the remaining 30g (⅓ c.) of sliced almonds
Bake for 40-50 minutes, until a toothpick inserted in the center of the cake comes out clean or with only a few moist crumbs. Let the cake cool in the pan until it's no longer too hot to touch, then use the parchment to lift the cake out of the pan.