Let me be clear about this up front: I have no idea what I've created here. As with my brown butter ricotta cookies, this is a culinary mistake that nearly wound up in the trash heap for falling so short of my aspirations. But ultimately, I discovered the only mistake was my unwillingness to accept this new creation on its own tender, chewy, cakey, pumpkin-spiced terms.
I'd originally set out to make a pumpkin blondie, based on the ultra fudgy white chocolate blondies in my cookbook. I wanted something that had a glossy crust, a gooey interior, and chewy edges, but with the flavor of pumpkin pie. What I got instead was something like pumpkin streusel muffins crossed with a coffee cake.
While a complete and total failure in the realm of fudginess, it managed to combine the best elements of those individual treats, baking up richer than a muffin, chewier than a coffee cake, and lighter than a blondie, with a hint of malt plus an autumnal aroma to rival pumpkin pie.
It's not a pumpkin cake. It's not a pumpkin muffin. It's not a pumpkin blondie. It's just a pumpkin...thing, and while I'm okay with that, calling it a "coffee cake" is the least confusing option available, because that at least helps convey its heartiness and density, if not its alluring richness and chew.
Another winning feature is its size, as the 10-inch cast iron skillet format yields the perfect amount for sharing with friends and family over brunch or afternoon tea (it bakes up much smaller than a 9- by 13-inch sheet cake, but it's much larger than a basic 8-inch round).
Making the Streusel Topping
The first step in this recipe is preparing the salty-sweet and spicy oatmeal streusel.
It's a buttery blend of rolled oats, flour (whether whole wheat or APF), brown sugar, loads of salt, and a host of autumnal spices, with raw pecans that will toast to a crisp in the oven and chunks of white chocolate that caramelize as they bake.
A stand mixer fitted with a paddle attachment will blend the dry ingredients into the soft butter without any fuss; in fact, if you're making the entire recipe all in one go, that's probably the easiest option.
But streusel is something I rarely make and use right away. Rather I'm in the habit of keeping a few bags in the freezer, so I always have a batch on hand for sprinkling over cakes, and pies, and cookies, and my life in general*. On those occasions, it's easier for me to whip the streusel up by hand than fuss with a stand mixer if I'm not using it for anything else.
*Perpetual access to ready-made streusel is, in fact, how this recipe evolved—a spur of the moment layer of crunch tossed over the pumpkin "blondie" batter on a whim.
However you make it, the process is stupid simple. Smush the butter into the dry ingredients, then add the white chocolate and pecans. Just remember that smush is the operative word; the blades of a food processor will only grind the oats into the butter, making for a sad, mealy streusel.
Once everything is smushed together, the streusel can be refrigerated while the pumpkin thing is underway, or frozen in an airtight container for several months (no need to thaw before use).
Making the Pumpkin Thing
The first step in making the pumpkin batter is combining the white chocolate with flour and malted milk powder (a.k.a. the umami bomb of dessert). This can be done by grating the white chocolate like Parmesan with a Microplane, then whisking it with the flour and malted milk powder, or by grinding everything together in a food processor. The latter is by far the fastest method, but the former is perfect for those without a food processor (or those who simply hate busting it out).
In either case, by reducing the white chocolate to a fine powder, cocoa butter and dairy solids will be distributed throughout the batter. This improves both richness and browning down the road. The malted milk powder plays a similar role, furnishing the batter with both maltose and powdered milk for a boost to flavor and complexity, as well as browning. Since it's not playing a structural role, feel free to omit the malted milk powder if it's not something you keep in stock, but it's an easy buy from most any supermarket, where brands like Carnation and Ovaltine (plain) are stocked right next to the hot cocoa mix. Otherwise, you can always pick up a big carton online from brands like Hoosier Hill Farms.
Like the streusel, this dry mix can be prepared in advance to split the recipe up into smaller, more manageable chunks; since it contains nothing but pantry staples, it can be stored in an airtight container at room temperature up until the earliest date stamped on its constituent parts. (For example, if the malted milk powder expires before the flour, it's the malted milk powder's shelf life that will determine how long the mix will be usable.)
With the dry mix and streusel prepared in advance, whether by a few moments or a few weeks, the pumpkin skillet thing itself comes together pretty fast. It starts with the classic creaming method that you'd see for any cookie, with the butter and sugar (plus spices, leavening, and vanilla) beaten together until creamy, soft, and light.
After adding an egg, the recipe veers into cake territory with the addition of liquid in the form of pumpkin purée (whether canned or homemade or "faked" with roasted butternut squash purée, my favorite hack for pumpkin pie), along with the malted white chocolate flour.
After scraping and folding the batter with a flexible spatula to ensure it's totally uniform throughout, I transfer it to a lightly buttered cast iron skillet.
The mixture turns out thicker than a cake batter but softer than cookie dough, so you will need to spread it out in an even layer. Once level, it's topped with the prepared streusel, and baked at 350°F until puffed and somewhat firm in the center, with the pecans and white chocolate visibly toasted; for me that takes about 35 minutes, with a few minutes less or more serving to push it closer to fudginess or cakiness, respectively.
Because the timing can vary depending on the exact shape and gauge of the cast iron skillet, it can be useful to check the internal temperature as a cross reference. The "cake" should hit approximately 205°F in the very center when a digital thermometer probe is inserted at a 45° angle and kept about 1/4 inch above the bottom of the skillet.
Thanks to all the melted cocoa butter in the batter, the interior will be quite molten while piping hot—wet, gooey, and seemingly underdone—so resist the temptation to dig in right away. But as it cools to room temperature, it will develop a texture that's much more cakey and light.
Whether passed off as a coffee cake at brunch, or served with coffee as an afternoon treat, it's a fun fall recipe that offers up all the flavors and aromas of the season in a cozy, cast iron package.