Heat the oven to 325°F. Stir together 1 Tablespoon canola oil and 1 Tablespoon all-purpose flour in a small bowl. Use a silicone baking brush to brush the mixture all over the insides of the cups of the muffin pans, making sure there are no large blobs of the mixture anywhere. Set the pans aside.
Add 8 ounces pitted Medjool dates and 1 cup water to a small saucepan. Bring to a boil over medium-high heat. Once the water starts to boil, remove the pot from the heat, cover, and let the dates sit in the hot water for at least 15 minutes.
Meanwhile, whisk together 2 cups all-purpose flour, 1 teaspoon baking powder, ½ teaspoon salt, and ½ teaspoon baking soda in a large bowl. Set aside.
Once the dates have been sitting for at least 15 minutes, transfer the date-water mixture to the bowl of a food processor, along with 1 cup dark brown sugar. Process until the dates are completely pureed and no lumps remain. Add 4 large eggs and 2 teaspoons vanilla to the food processor and process again. While the food processor is running, slowly pour in the melted butter.
Pour the date mixture into the bowl with the flour mixture, and whisk to combine until no more flour lumps remain. Pour the batter into the prepared muffin pans, filling the cups only 2/3 to 3/4 full, ensuring that you leave 1/3 to 1/2-inch (approximately 1-1.25 cm) at the top of the cup so that the batter doesn't overflow to make a large dome. Bake for 20-25 until a toothpick inserted into the center of one of the cakes comes out with a few crumbs clinging to it. (See the notes section for baking times if using other pan types).
Cool the cakes in the pan for 5-10 minutes, then run a paring knife around the edges of each cup to release the cakes. Cool for another 20-25 minutes on a wire rack.
Toffee Sauce
Add ¾ cup whipping cream, 12 Tablespoons unsalted butter, ¾ cup dark brown sugar, 6 Tablespoons corn syrup, and ½ teaspoon salt to a small to medium saucepan. Fit the saucepan with a candy thermometer, or get an instant-read thermometer ready. Bring the mixture to a boil over medium heat. Continue heating, stirring often, until the mixture reaches 240°F, about 15-20 minutes. Remove the saucepan from heat and stir in 2 teaspoons vanilla. Let the mixture cool slightly before serving.
To Serve
Place one cake in a small bowl or plate. Top with a small amount of warm toffee sauce, and place a small dollop of whipped cream or scoop of vanilla ice cream on top of that, if desired.
Notes
Cooking Times for Different Cake Pans: To bake in a Bundt pan, bake at 325°F for 40 minutes to one hour.To bake in a 9x13" pan, bake at 325°F for 35-40 minutes. In both cases, insert a toothpick into the center of the cake. It should come out with a few crumbs clinging to it when done.To Make Ahead:If you want to make your sticky toffee pudding in advance, follow the instructions as written. Allow the cakes to cool completely to room temperature, then place them in an airtight container or zipper bag. If you plan to serve the dessert in the next couple of days, store the cakes in the fridge. If it will be longer than that, put them in the freezer. Thaw at room temperature for at least 4-6 hours before serving.Allow the toffee sauce to cool for at least 30 minutes, then carefully pour it into an airtight container or jar and store it in the fridge. Pour the sauce back into a small saucepan to reheat it before serving (heat over medium-low heat, don't bring it to a boil).