Almond Rum Butter Cream Apple Pie (or Tarte Bourdaloue aux Pommes)

I’d been craving a sweet apple-something for about three weeks, yet forgetting to purchase apples any time I went to the grocery store in that time. Inspired by my mister’s purchase of salted caramel ice cream and further inspired by having made a big batch of pastry that needed to be used up, I finally…