Preheat your oven to 350°F (180°C) then butter and line a 9-inch spring form pan. Set aside.

For the Streusel ToppingIn a medium bowl, combine the flour, sugar, oats and salt. Using your finger tips or a fork, rub in the cold butter until you've reached the texture of coarse breadcrumbs. Set aside in the fridge while you make the cake.

For the Irish Apple CakeCream the butter and sugar together in a large bowl until light and fluffy.

Next, beat in the eggs one at a time until combined. Lastly stir in the vanilla.

In a separate medium bowl combine the flour, baking powder cinnamon, and salt.

Fold the dry ingredients into the wet along with the milk.

Once the batter has formed, transfer it to the prepared cake pan and lay on the sliced apples, making sure they are arranged in one even layer.

Cover the apples with all the streusel topping. Press down gently with your hand.

Bake for roughly 65-75 minutes, or until the top is golden brown all over and crisp. Remove from the oven and allow cooling slightly before turning out of the tin.

When ready to serve, dust the cake with powdered sugar, slice and enjoy. Store the cake in an airtight container at room temperature for up to 4 days.