Center a rack in the oven and preheat it to 350 degrees F. Coat a 9-x-9-inch baking pan with baker’s spray and run a sheet of parchment paper over the bottom and up two opposite sides, leaving enough overhanging paper to grab and lift the baked cake out of the pan. Or butter the pan, dust the interior with flour, tap out the excess and line it with the paper.

To make the crunch: Toss all the ingredients together; set aside.

To make the cake: Stir the espresso powder and boiling water together in a small cup; set aside.

Whisk the flour, baking powder, cinnamon and salt together.

Working in the bowl of a stand mixer fitted with the paddle attachment, or in a large bowl with a hand mixer, beat the butter and both sugars together on medium speed until well blended, about 3 minutes; scrape the bowl and beater(s) early and often. The mix will seem pasty, and that’s fine. One by one, add the eggs, beating for a minute after each one goes in. Don’t be concerned if the mixture looks as though it’s on the verge of curdling or even if it curdles—it’ll smooth out soon.

With the mixer running, beat in the oil, followed by the espresso mixture and vanilla. Turn off the mixer, add one-third of the dry ingredients and mix on low until they almost disappear. With the mixer running, gradually pour in half of the coconut milk. Scrape, add half of the remaining dry ingredients and mix on low until they almost disappear, then blend in the rest of the coconut milk. Scrape, and mix in the rest of the dry ingredients. You’ll have a thick, creamy, easily spreadable batter.

Scrape half of the batter into the pan, then use an icing spatula or a knife to nudge it into the corners and to smooth the surface. Scatter the crunch mixture evenly over the batter—don’t miss the edges—and top with the remaining batter, taking care to again smooth the top. Take the crumbs out of the refrigerator and, if they need it, smush and press them into curds or clumps before topping the cake with them.

Bake for 38 to 43 minutes, or until the cake is risen and richly browned and can be pulled from the sides of the pan when gently nudged; a tester inserted into the center of the cake will come out clean. Transfer the pan to a rack and let it rest for 10 minutes, then use the parchment handles to lift the cake out of the pan and onto the rack. Turn the cake over onto another rack, carefully peel away the paper and then invert back onto the rack to cool until just warm or at room temperature.

When ready to serve, give the top of the cake a light dusting of confectioners’ sugar, if you’d like.