To make salted caramel sauce (this can be done up to five days ahead): Bring sugar and water to a boil in a small saucepan over medium-high heat, stirring to dissolve sugar. Once it comes to a boil (this should happen quickly), continue cooking on medium-high heat, swirling pan occasionally and brushing down sides with a wet pastry brush, until mixture turns a deep amber color (this should take about 8–10 minutes - err on the side of remove pot from heat a bit earlier rather than later, because caramel burns EASILY). Remove from heat and add cream slowly, stirring very gently (mixture will bubble vigorously).

Return to medium heat and cook, stirring occasionally, until smooth, about a minute. Remove from heat and mix in butter and salt. Pour caramel sauce into a small heatproof jar or bowl, let cool, and stir until ready to use.

Preheat oven to 350F or 170C. Boil some water for tea, and make a strong cuppa - out of two tea bags, preferably. Peel and core apples, and slice into thin crescents.

In a large bowl, whisk together sugar, oil, apple butter, honey, eggs and cinnamon.

Sift both types of flour into bowl through a flour sifter, or a colander, in order to avoid lumps. Add baking powder, and whisk to combine.

Add boiling hot tea to bowl in 2-3 pours, whisking constantly to combine.

Generously oil a springform pan. Arrange apple slices in a single layer at the bottom of the pan, fanning them out in circles. Pour cake batter on top.

Bake cake in a 350F oven for 45 minutes, or until a toothpick inserted in the middle comes out clean, and cake is firm but springy. Let cool a bit, then run a knife around the sides and under the bottom, cover pan with a plate, and remove cake from springform pan, turning it onto the serving plate with the apple slices on top.

Serve cake with whipped cream and salted caramel sauce on top, just with salted caramel sauce, just with whipped cream, or just as is.