For Individual Ramekins:

1️⃣ Preheat Oven:
Preheat oven to 375°F (190°C). Coat six 4-ounce ramekins with nonstick cooking spray and place them on a baking tray.

2️⃣ Make the Cake Batter:
In a food processor, combine butter, baking soda, salt, both sugars, eggs, vanilla, and flour. Pulse until just combined. Add the prunes and hot water, then pulse again until the mixture is nearly smooth.

3️⃣ Fill and Bake:
Spoon the batter into the ramekins, filling each about 2/3 full. Bake for 18 minutes, or until the cakes are just firm to the touch and spring back when pressed lightly. Remove from the oven and allow to cool slightly.

4️⃣ Prepare the Toffee Sauce:
In a medium saucepan, combine butter, heavy cream, brown sugar, and sea salt. Cook over medium-high heat, whisking continuously, until the mixture bubbles gently. Reduce the heat to medium-low and cook, stirring often, until the sauce thickens and coats the back of a wooden spoon (about 3-4 minutes).

5️⃣ Assemble and Broil:
Slice each cake in half horizontally. Place the bottom halves back in the ramekins and drizzle with some toffee sauce. Replace the tops and drizzle more sauce over each. Place under the broiler, 4 inches from the heat, for 1-2 minutes, until bubbly and sticky. Watch closely to prevent burning.

6️⃣ Serve:
Turn out the cakes onto individual plates, drizzle with additional toffee sauce, and garnish with whipped cream or a drizzle of heavy cream. Serve warm.

For a Single Baking Dish:

1️⃣ Bake the Cake:
Grease an 8×8-inch square baking dish and pour in the batter. Bake at 375°F (190°C) for 15 minutes, then tent with foil and bake for another 15 minutes. Check for doneness 1-2 minutes before the end; a tester should come out clean. Cool slightly before slicing.

2️⃣ Serve:
Slice into squares, drizzle with warm toffee sauce, and garnish as desired.