Preheat oven to 180° C. Line the square pan (22 x 22 cm) with baking paper.
In a large bowl, mix together the dry ingredients: oat flour, almond flour, date sugar, turmeric powder (optional), gingerbread or pumpkin pie spice mix, and baking powder.Note: If you have celiac disease or gluten sensitivity, always make sure to buy certified gluten-free oat and almond flour to avoid possible cross-contamination.
Add sweet potato puree (check How to make sweet potato puree for instructions), almond butter, lemon juice, rice milk, and freshly grated lemon zest, and mix everything together with a hand mixer until properly combined. Adjust sweetness if needed.
Pour the batter into the prepared pan and bake for approx. 40-45 minutes.
Remove from the oven and let it cool fully before serving. Slice and serve.
