Preheat the oven to 350 degrees F. Grease a 9x13-inch baking pan.
In a medium bowl, whisk together the flour, oat flour, baking powder, and salt.
Lightly beat the eggs.
Add the eggs and the rest of the ingredients to the flour mixture. Stir gently with a spatula to combine.
Add the batter to the prepared cake pan.
Bake until a toothpick inserted in the center of the cake comes out clean, and the edges are lightly golden brown and the center is set, about 22-24 minutes. Let cool fully on a wire rack.
Strawberry Frosting: Add all ingredients to a medium bowl. Use a hand held electric mixer to beat until very smooth, starting on a low speed and working up to high.
Spread Strawberry Frosting over cooled cake and slice. Top with fresh berries if desired to serve.
Notes
Store frosted cake fully covered in the fridge for up to 24 hours before serving. Let sit at room temperature for about 30 minutes before serving. Store any leftovers in an airtight container in the fridge for up to 3 days.
Choose a strawberry jam that’s relatively smooth or try not to use large pieces of berries to ensure that the frosting is smooth.
Use additional all purpose flour in place of the oat flour if desired.