Although I don’t ever recall my grandmother actually making Heath bar cake for me, when I stumbled upon her recipe (see the photo below) for such a treat in her tattered, blue, three ring binder, there was no question I’d be trying my hand at one, and these Heath bar coffee cake muffins were born. And I’m not even some crazy lover of Heath bars. Instead, I’m just a sucker for a cake filled with candy. I mean, who isn’t? 
Googling and cookbook-perusing immediately ensued, as I searched to see if Heath bar cake had indeed been a trendy dessert at some point in the past. And so it was that I stumbled upon almost the exact replica of my grandmother’s recipe for toffee coffee cake and candy bar toffee cake. Candy cake recipe development began in earnest. 
My first go-around with Heath bar cake ended up in baked occasions, as the “toffee coffee cake,” and requires that you make your own toffee. But this revamp of my grandmother’s Heath bar cake is closer to the original and calls for store bought Heath bar bits (you’re welcome). It also adapts the unusual mixing method of my grandmother’s, whereby the dry ingredients are mixed with the butter and then all of the wet is added at once. Kind of one bowl-esque and kind of genius, as it is super easy and fast and makes for the moistest and fluffiest of coffee cakes. Or coffee cake muffins as the case may be (the extra yolk and oil I added didn’t hurt either).
And so, candy cake fans, and even those unsure of where they stand re: candy-filled cake, give these muffins a whirl. You will not be sad you did when you find yourself biting into a delectable little cake with a swirl of toffee and nuts and a crumbly candy studded top and wonder – happily – why candy has not made its way into more of your sweets and treats. And if I have my way, it will . . .
vanilla bean heath bar coffee cake muffins
Ingredients
- 1/4 cup unsalted butter cold
- 1/4 cup oil
- 1 cup cake flour
- 1 cup all-purpose flour
- 1/2 tsp salt
- 3/4 cup light brown sugar
- 3/4 cup granulated sugar
- 5 ounces toffee bits such as heath bar, plus more bits for topping each muffin
- 1/3 cup walnuts toasted and roughly chopped
- 1 large egg
- 1 yolk
- 1 cup sour cream
- 1 tsp baking soda
- 1 Tbsp vanilla bean paste or one vanilla bean, scraped
Instructions
- preheat the oven to 350 degrees and line a 12 cup muffin tin with cupcake liners and - if you have two tins - line the second one with 6 liners.
- place the butter, oil, flours, salt and sugars in the bowl of a stand mixer, and using your hands, work the butter and oil into the dry ingredients until crumbly. remove 1/2 cup of this mixture, add the toffee bits and walnuts to it, and set aside.
- place the bowl on the stand mixer, fitted with the paddle attachment, add the egg, yolk, sour cream, baking soda and vanilla paste, and beat on medium-high to high speed for 3 minutes, scraping down the bowl with a rubber spatula periodically, if necessary.
- remove the bowl from the mixer. place a tablespoon and a half of batter in the bottom of each cupcake liner, using a small offset spatula or spoon to make sure the batter evenly covers the bottom of the liner, add a tablespoon and half of the reserved toffee/nut crumb, and another tablespoon and a half of batter. top each muffin with a sprinkling of candy bits.
- place one tray at a time into the oven, again, making sure the batter covers the toffee mixture by spreading it with an offset spatula or spoon. and bake for 18 to 20 minutes, rotating each pan halfway through the baking time. remove the muffins from the oven when a toothpick comes out with a moist crumb or two. let the muffins cool slightly before removing them from the pan and allow them to continue to cool on a wire rack - or don't and eat them warm from the oven.
Notes
make sure the toffee bits are encased in batter (by spreading the batter to the edges of the cupcake liner) to avoid having your toffee stick to the liners, making removal of said liners from the muffins a bit messy.