Thick & Soft Gluten-Free Coffee Cake

recipe by: Sarah Menanix

yields: slices or one 8-inch square or 9-inch round coffee cake

prep time: 25

cook time: 1

total time: 1 25

Fluffy and super moist gluten-free coffee cake made with oat and almond flours! There's a ribbon of cinnamon sugar, a thick layer of cinnamon streusel, and an optional drizzle of vanilla icing. This classic bakery-style coffee cake is perfect for brunch or dessert.

5 from 8 reviews

Ingredients

Cinnamon Crumble

42 g (¼ cup + 2 tablespoons) super-fine blanched almond flour
20 g (2 tablespoons) sweet rice flour, also called mochiko; do not substitute white or brown rice flour
21 g (3 tablespoons) gluten-free oat flour
50 g (¼ cup) light brown sugar
26 g (2 tablespoons) granulated sugar
1¾ teaspoons ground cinnamon
¼ teaspoon kosher salt
¼ cup unsalted butter, melted

Cinnamon Swirl

20 g (3 tablespoons) gluten-free oat flour
7 g (1 tablespoon) super-fine blanched almond flour
75 g (¼ cup + 2 tablespoons) light brown sugar
1 teaspoon ground cinnamon

Vanilla Cake

95 g (¾ cup + 2 tablespoons) gluten-free oat flour
110 g (½ cup + 3 tablespoons) sweet rice flour, also called mochiko, different from "white rice flour" or "brown rice flour"
42 g (¼ cup + 2 tablespoons) super-fine blanched almond flour
½ teaspoon xanthan gum, optional, see note
1¼ teaspoons baking powder
½ teaspoon baking soda
½ teaspoon kosher salt
½ cup (8 tablespoons) unsalted butter, room temperature
175 g (¾ cup + 2 tablespoons) granulated sugar
2 large eggs, room temperature
1½ teaspoons pure vanilla extract
½ cup full-fat sour cream, room temperature

Vanilla Icing

¾ cups (86 g) powdered sugar, sifted
2-3 tablespoons whole milk
1 tablespoon unsalted butter, melted
½ teaspoon pure vanilla extract

INSTRUCTIONS

Preheat the oven to 350°F and line the bottom and sides of an 8x8 square baking pan with parchment paper, or use a 9-inch round springform pan.
Begin by making the cinnamon crumble. Mix together the almond flour, sweet rice flour, oat flour, brown sugar, sugar, cinnamon, and salt in a small bowl. Pour the melted butter over the top and mix with a fork until completely moistened and it holds together when pinched. If you prefer a clumpy crumble like I do, place the crumble in the fridge while you prepare the rest. Otherwise, set aside.
Next prepare the cinnamon swirl. Mix together the oat flour, almond flour, light brown sugar, and cinnamon in a small bowl. Set aside.
Prepare the cake batter. Sift together the oat flour, sweet rice flour, almond flour, xanthan gum, baking powder, baking soda, and salt in a medium mixing bowl. Set aside.
In the bowl of a stand mixer fitted with the paddle attachment or a bowl with a hand mixer, cream together the butter and sugar over medium speed until light and fluffy, about 3 minutes.
With the mixer on low speed, add the eggs one at a time, mixing and scraping down the sides after each one. Add the vanilla extract, mixing until just combined.
Keeping the speed on low, slowly add the dry ingredients in two batches, alternating with the sour cream and mixing until just combined.
Scrape half of the batter into the prepared baking pan and use an offset spatula to spread it into an even layer. Sprinkle the cinnamon filling in an even layer over the top.
Carefully dollop the remaining batter over the cinnamon filling and carefully spread it into an even layer with an offset spatula. It's normal if your cake batter is thick, just dollop, work slowly to spread, and do the best you can. It doesn't have to be perfect here.
Sprinkle the cinnamon streusel evenly over the top, clumping it together as you go. Bake the cake for 60-65 minutes or until a cake tester comes out clean or with just a few moist crumbs. When gently tapped, the center should spring back and not indent at all. If the center wobbles or doesn't seem firm under the streusel, bake for up to 5 minutes longer.
Place on a wire rack and cool for at least 20-30 minutes before serving. See post above about serving the cake warm.
Make the vanilla icing. Whisk together the powdered sugar, 2 tablespoons of milk, butter, and vanilla extract. If the icing is too thick, add up to another tablespoon of milk until it can be easily drizzled. Drizzle over the cake. Cut into 9-16 squares or rectangles (3x3, 4x4, or 3x4) and serve warm or room temperature.

Notes

SUBSTITUTIONS:

Xanthan Gum: The xanthan gum is optional. Adding it will make your cake a little fluffier and less dense with springy chew more like a regular cake. Rest assured, this recipe has been tested both ways and is delicious with and without.

Gluten-Free Oat Flour: Gluten-Free Oat flour helps create fluffiness and retain moisture in the cake.

Option: grind up gluten-free rolled oats in a food processor or blender, then sift out any big pieces. Make sure to measure this by weight as homemade gluten-free oat flour is less finely ground so the volume per weight will be different.
Sub in by weight: All-purpose gluten-free flour.

Sweet Rice Flour: Also called mochiko or glutinous rice flour, sweet rice flour is distinctively different than white rice or brown rice flour. Sweet rice flour is the same flour used to make mochi, and as such, its stickiness helps to bind the cake together, creating chewiness like a classic cake recipe. Sweet rice flour is the most difficult flour to substitute in gluten-free baking and I don’t recommend it.

Sub in by weight: Tapioca flour or all-purpose gluten-free flour. I tested a version of this cake that used half sweet rice flour and half tapioca starch and it was equally delicious. For the sake of a simpler recipe, I cut out the tapioca flour. While I haven't tested replacing all the sweet rice flour with tapioca flour/starch, it is what I would try first if necessary. Alternatively, I would try subbing in all-purpose gluten-free flour by weight.

Superfine Blanched Almond Flour: In this recipe, almond flour adds moisture and subtle warm and cozy flavor notes to the coffee cake. Its texture is more neutral to the overall crumb.

Sub in by weight: millet flour, teff flour (though your cake will be noticeably darker), light chestnut flour, brown or white rice flour, or all-purpose gluten-free flour.

Sour Cream: If you don't have sour cream, you can sub in whole milk plain or greek yogurt, but your results may not be quite as moist or rich in flavor. You can also sub in creme fraiche and add a tablespoon of lemon juice for tang, if desired.

VARIATIONS:

Chopped Fruit: Fold fresh fruit directly into the batter. Earlier this fall I made a variation of this cake with chopped apples. Add about 1½ cups peeled chopped apples directly to the batter. You can also add whole blueberries, cranberries, or raspberries, or fresh chopped strawberries, but only add about 1-1¼ because they'll release quite a bit of moisture. You can fold these directly into the batter or layer them on top of the batter underneath the streusel. If adding fruit, I would skip the cinnamon ribbon for simplicity and add cinnamon directly to the batter, if desired.

Fruit Ribbon: Replace the cinnamon ribbon with a thin layer of fruit preserves.

Spices: Add ground cardamom, cinnamon, ginger, nutmeg, or other favorite spices to the cake batter or streusel. Or fold in a tablespoon of freshly grated ginger.

Nuts: Add ¼ cup sliced almonds, chopped pecans, chopped walnuts to the streusel.

Powdered Sugar: Dress it up quickly by dusting the streusel with powdered sugar in place of the glaze.

Graham cracker coffee cake: Replace up to 60g of the oat flour in the cake with ground up gluten-free graham crackers and sub out all the flours in the crumble for ground-up graham crackers by weight for a gluten-free graham cracker coffee cake variation.

** Almost every cake recipe will tell you to let the cake cool completely before icing and slicing, but in my opinion, this gluten-free cinnamon swirl coffee cake is excellent served warm. This means it gets from oven to fork even quicker!

When it comes out of the oven, let it cool for about 20-30 minutes before drizzling with glaze.

You can also make the cake in advance and serve it at room temperature and it's equally delicious and moist. You can also zap room temperature or chilled cake for 10-20 seconds in the microwave to heat it up, if that's your style.