Oatmeal Cake

This oatmeal Cake is rich, moist, and packed with warm Spices — and that broiled coconut topping? It caramelizes right into the Cake and takes the whole thing to another level. Forget a plate. You’ll be eating this straight from the pan.

Why You’ll Love It

Incredibly moist crumb — the oatmeal works into the batter and gives it this pillowy, almost ooey-gooey texture that’s unlike any other cake
Warm spices in every bite — cinnamon and nutmeg hit at the back of the bite in the best way
That broiled coconut topping — sticky, caramelized, and chewy, it melts right into the top of the cake like a praline-meets-German-chocolate-frosting situation
One pan, no fuss — mix it, bake it, top it, broil it, done
Gets better as it sits — the topping becomes even chewier the next day, if it lasts that long

A Few Notes on Ingredients

The oatmeal situation: use old-fashioned rolled oats, not the quick-cooking kind. The quick oats turn to mush and you lose that little bit of texture that makes this cake what it is. I’ve made that mistake — early on, in a hurry — and it’s fine, but it’s not the same. The oats need to soak in boiling water for a solid twenty minutes, and don’t skip that step. Don’t even think about it.
Butter: real butter. Both in the cake and in the topping. I’m not going to argue about this.
The coconut in the topping should be sweetened. I’ve seen recipes that call for unsweetened and I tried it once when that was all I had — it works, but it’s different. More austere. Less gooey. If you like austere, do what you want.
Nuts — I use pecans, finely chopped. Walnuts work too. Whatever is on sale is honestly fine. All three versions are delicious, which is either comforting or annoying depending on your personality.
Evaporated milk, not sweetened condensed. Don’t mix those up. I did, once, maybe fifteen years ago with a different recipe, and the result was baffling.

Ingredients

For the Cake:

1 1/4 cups boiling water
1 cup old-fashioned oatmeal, uncooked
1/2 cup butter (softened)
1 cup sugar
1 cup brown sugar, firmly packed
2 eggs
1 teaspoon vanilla
1 1/2 cups all-purpose flour
1 teaspoon baking soda
3/4 teaspoon cinnamon
1/2 teaspoon salt
1/4 teaspoon ground nutmeg

For the Topping:

1/2 cup butter
2 cups sweetened shredded coconut
1 cup pecans (or walnuts), finely chopped
1 1/2 cups brown sugar, firmly packed
8–10 tablespoons evaporated milk (start with 8, see how it looks)

Let’s Make It

Preheat your oven to 350 degrees. Pour the boiling water over the oatmeal in a bowl and leave it alone. Twenty minutes, minimum. Go do something else — fold laundry, answer an email, stand at the window and think about nothing in particular. The oats need to absorb and soften.
When they’re ready, Cream your butter with both sugars. I use a hand mixer because I am not dragging out the stand mixer for this — it’s not that kind of cake. Once it’s well combined, add your eggs one at a time and beat well. Then stir in the vanilla and the oatmeal mixture. Don’t panic at how the batter looks at this point — it’s a little strange, kind of chunky. That’s normal.
Add your flour, baking soda, salt, cinnamon, and nutmeg. Mix until it just comes together. Don’t over-mix — I always say that and I always mean it.
Pour into a greased 9×13 pan. Bake for 30 minutes. You’ll know it’s done when it’s set in the middle and the edges are just pulling away from the sides.
Now the topping — and this part moves fast, so have it ready before the cake comes out of the oven. Melt the butter in a saucepan over medium heat. Add the coconut, nuts, brown sugar, and evaporated milk. Stir it all together until the sugar dissolves and everything is combined. It’ll be thick and a little loose. That’s what you want.
The second you pull the cake from the oven, spread the topping over it. Don’t wait. The heat from the cake helps everything meld together, and some of that caramel-y topping will sink into the top just slightly.
Then put it under the broiler. Stay there. Don’t walk away. Don’t go check your phone. Stand at the oven and watch it — usually three to four minutes is all it takes, but broilers vary and the line between “gorgeous and golden” and “oh no” is narrow. Pull it when the top is dark and bubbling and smells like burnt caramel in the good way, not the bad way.

Variations

This cake is great without the nuts if texture is a thing for you — just go full coconut in the topping and it’s still fantastic, just a little more tropical-leaning.
I once tried adding a handful of mini chocolate chips to the batter because I had them and thought, why not. They melted in and disappeared almost entirely and the cake tasted basically the same. A little richer maybe. Not sure it was worth it. Probably wouldn’t do it again.
If you want to cut the sweetness, which I understand — this is an unambiguously sweet cake — you can reduce the brown sugar in the topping slightly. I’ve done 1 cup instead of 1 1/2 and it’s fine. Still good. Still gooey. Just a bit less. Whether that’s a feature or a problem is up to you.

Storage

This cake keeps well at room temperature, loosely covered, for a couple of days. The topping gets even chewier and more caramelized as it sits, which I personally think is an improvement. You can refrigerate it but the texture of the topping goes a bit harder — not bad, just different. I usually leave mine on the counter under a piece of foil and work through it slowly over two days.