Preheat the oven to 350°F/180°C/Gas 4. Spray a bundt pan with nonstick baking spray and set it aside.

To make the cake, whisk or sift the flour, cinnamon, baking powder, baking soda, and kosher salt into a bowl.

Place the butter into a medium-size microwave-safe bowl. Melt butter in the microwave, and once melted, add the brown sugar and eggs.

Use an electric handheld or standing mixer to beat the wet ingredients together.

Then while mixing, slowly add the dry ingredients to the wet ingredients until just combined.

Gently fold the diced apples into the cake batter.

Pour cake batter into the prepared bundt pan. Smooth the top of the cake and bake in the preheated oven for 60 minutes, or until an inserted toothpick comes out clean.

Remove the cake from the oven and leave it to cool in the pan for 15 minutes before turning it out onto a wire rack to cool completely.

To make the toffee sauce topping, Place the butter into a medium-size saucepan and set it on medium heat.

As the melted butter begins to foam add the brown sugar and vanilla. Stir ONCE only.

Keep the saucepan on medium heat for 5 minutes or until the mixture begins to bubble and turns to the color of maple syrup.

Very slowly add the heavy cream while stirring continuously.

Cook the toffee sauce for 2 minutes. The sauce will bubble and increase in size.

Remove from toffee topping from the stovetop and carefully drizzle over the top of the cake. Dust with ground cinnamon if desired.

Allow the topping to cool before slicing the cake to serve. Enjoy!