Bake your cake in two rounds. Slice them length wise so you have 4 circles.
Place a circle (might have to trim down) in the bottom of a trifle dish.
Make your homemade whip cream (whip heavy cream until soft peaks form, add handful or more (to taste) of powdered sugar, and a tsp. vanilla). Pour heated hot fudge sauce on cake layer. Sprinkle toffee on top of hot fudge. Add a layer of whip cream.
Start over until you reach the top. Exaggerate your layers more on the sides so that they look more like "layers" (more toffee against glass, smear whip cream, and fudge against glass, etc.)
Notes
Tip: Exaggerate your layers along the glass a little more so they show up as "layers" and not all muddled together. So...sprinkle extra toffee on the sides, smear up the whip cream and hot fudge on the glass a little to encourage the layered look.