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My mother had a rule about crumb cake, and she said it often enough that my brothers could recite it: if the crumb is thinner than the cake under it, it is not crumb cake, it is a coffee cake with a rumor on top. Every Sunday in October, when the apples from the orchard were at their best and the kitchen was finally cold enough to want the oven on, she made this one. The crumb was piled so high I always thought it would never bake through. It always did, and my brothers always picked the crumbs off the corner pieces before anybody else got to them.
The secret of a proper crumb is not in the ingredients, it is in the hands. Cold butter is rubbed into brown sugar, flour and cinnamon until it looks like damp sand, and then you squeeze handfuls of it together and break them apart into lumps about the size of a thumbnail. Those lumps bake crisp on top and stay soft and buttery underneath. The cake itself is a thick, tender sour cream batter, and between two layers of it sits a layer of thin apple slices tossed in cinnamon sugar. Chill the crumb while you make the batter and the lumps stay big in the oven.
Why this apple crumb cake works
- As much crumb as cake. The topping uses nearly as much flour and butter as the cake. That is what makes it crumb cake and not coffee cake.
- Squeezed lumps. Pressing the crumb mixture into clumps before scattering it gives big crisp pieces instead of a thin sandy layer.
- Cold crumb. Chilled butter holds its shape in the oven, so the lumps do not melt into the batter.
- Sour cream batter. Sour cream makes a thick, tender, slightly tangy cake strong enough to hold up a heavy topping.
- Apples in the middle. A layer of thin slices bakes soft and jammy inside the cake and keeps it moist for days.
Ingredients
Makes one 9x13 inch cake, about 16 squares. The measurements are in US cups with grams in brackets.
For the crumb topping
- 1 1/2 cups all-purpose flour (190g)
- 1 cup packed light brown sugar (200g)
- 1 1/2 teaspoons ground cinnamon
- 1/4 teaspoon fine salt
- 3/4 cup cold unsalted butter, cut in pieces (170g)
For the cake
- 2 1/4 cups all-purpose flour (280g)
- 1 teaspoon baking powder
- 1/2 teaspoon baking soda
- 1/2 teaspoon fine salt
- 1/2 cup unsalted butter, softened (113g)
- 1 cup granulated sugar (200g)
- 2 large eggs
- 1 cup sour cream (240g)
- 2 teaspoons vanilla extract
For the apple layer
- 3 medium apples, peeled and thinly sliced (about 3 cups, 375g)
- 2 tablespoons granulated sugar (25g)
- 1 teaspoon ground cinnamon
To finish
- 1 tablespoon powdered sugar, for dusting
Firm, tart apples hold their shape best: Granny Smith, Honeycrisp, Jonagold or a mix. Slice them thin, about the thickness of a nickel, so they soften fully in the middle of the cake.
How to make apple crumb cake
- Make the crumb first. In a bowl, mix the flour, brown sugar, cinnamon and salt. Rub in the cold butter with your fingertips until it looks like damp sand. Squeeze handfuls together, then break them into lumps about the size of a thumbnail. Put the bowl in the refrigerator.
- Heat the oven to 350 degrees (175°C). Grease a 9x13 inch baking pan.
- Toss the sliced apples with the 2 tablespoons sugar and the cinnamon and set aside.
- Whisk the flour, baking powder, baking soda and salt in a bowl.
- In a large bowl, beat the softened butter and sugar until pale and fluffy, about 3 minutes. Beat in the eggs one at a time, then the sour cream and vanilla. Stir in the dry ingredients just until no flour shows. The batter will be thick.
- Spread half of the batter in the pan. Lay the apple slices over it in an even layer. Drop the rest of the batter over the apples in spoonfuls and spread it gently to cover them.
- Take the crumb from the refrigerator and scatter it thickly over the whole cake, keeping the lumps big. It will look like too much. It is not.
- Bake at 350 degrees for 45 to 50 minutes, until the crumb is golden brown and a toothpick in the center comes out with no wet batter. Cool in the pan at least 30 minutes, dust with powdered sugar and cut into squares.
Tips that make the difference
- Do not skip chilling the crumb. Ten minutes in the refrigerator is the difference between lumps and sand.
- If the crumb browns before the center is done, lay a sheet of foil loosely over the pan for the last 10 minutes.
- Spread the top layer of batter with a wet spoon so it glides over the apples without dragging them.
- Cut with a serrated knife and a gentle sawing motion so the crumb stays on the cake.
Variations
- Pecan crumb. Add 1/2 cup chopped pecans to the crumb mixture for a crunchier topping.
- Pear. Use ripe but firm pears in place of the apples, sliced the same way.
- Glaze. Drizzle a thin glaze of powdered sugar and milk over the cooled cake instead of dusting it.
- Spiced. Add 1/4 teaspoon nutmeg and a pinch of cloves to the apple layer for a darker autumn taste.
Storage and make-ahead
Keep the cake covered with a clean towel or loosely with foil at room temperature for up to 2 days. Plastic wrap softens the crumb.
Refrigerate for up to 5 days and warm squares for a few seconds before serving.
Freeze cut squares wrapped in plastic and foil for up to 2 months. Thaw on the counter and crisp in a warm oven for 5 minutes.
Frequently asked questions
Why did my crumb topping melt into the cake?
The butter was too warm or the crumbs were too fine. Use cold butter, squeeze the mixture into big lumps, and chill it before it goes on the cake.
Can I make it in a smaller pan?
Halve everything and bake it in an 8 inch square pan for about 35 to 40 minutes, checking with a toothpick.
Do I have to peel the apples?
My mother always did, because peels turn chewy inside a cake. Peeled thin slices melt into the middle layer.
Can I make it the day before?
Yes. It keeps beautifully and the apple layer is even better on the second day. Dust with powdered sugar just before serving.
As much crumb as cake, big lumps, and apples in the middle. Bake it on a cold Sunday and keep an eye on the corner pieces.
Apple Crumb Cake with a Crumb as Thick as the Cake
Old-fashioned apple crumb cake: a tender sour cream cake with a layer of cinnamon apples in the middle and a thick topping of big buttery brown sugar crumb lumps, baked in a 9x13 pan at 350 degrees.
Ingredients
- 1 1/2 cups all-purpose flour
- 1 cup packed light brown sugar
- 1 1/2 teaspoons ground cinnamon
- 1/4 teaspoon fine salt
- 3/4 cup cold unsalted butter, cut in pieces
- 2 1/4 cups all-purpose flour
- 1 teaspoon baking powder
- 1/2 teaspoon baking soda
- 1/2 teaspoon fine salt
- 1/2 cup unsalted butter, softened
- 1 cup granulated sugar
- 2 large eggs
- 1 cup sour cream
- 2 teaspoons vanilla extract
- 3 medium apples, peeled and thinly sliced
- 2 tablespoons granulated sugar
- 1 teaspoon ground cinnamon
- 1 tablespoon powdered sugar, for dusting
Instructions
- Make the crumb first. In a bowl, mix the flour, brown sugar, cinnamon and salt. Rub in the cold butter with your fingertips until it looks like damp sand. Squeeze handfuls together, then break them into lumps about the size of a thumbnail. Put the bowl in the refrigerator.
- Heat the oven to 350 degrees (175°C). Grease a 9x13 inch baking pan.
- Toss the sliced apples with the 2 tablespoons sugar and the cinnamon and set aside.
- Whisk the flour, baking powder, baking soda and salt in a bowl.
- In a large bowl, beat the softened butter and sugar until pale and fluffy, about 3 minutes. Beat in the eggs one at a time, then the sour cream and vanilla. Stir in the dry ingredients just until no flour shows. The batter will be thick.
- Spread half of the batter in the pan. Lay the apple slices over it in an even layer. Drop the rest of the batter over the apples in spoonfuls and spread it gently to cover them.
- Take the crumb from the refrigerator and scatter it thickly over the whole cake, keeping the lumps big. It will look like too much. It is not.
- Bake at 350 degrees for 45 to 50 minutes, until the crumb is golden brown and a toothpick in the center comes out with no wet batter. Cool in the pan at least 30 minutes, dust with powdered sugar and cut into squares.
