In the bowl of a stand mixer, measure out 1 cup brown rice flour, sorghum flour, potato starch, tapioca starch, xanthan gum, salt, 3/4 cup granulated sugar and baking powder and mix until well combined.
In a small bowl, whisk together 1 cup milk, eggs, 1 1/2 tsp vanilla extract and oil.
With the mixer running, slowly pour the wet ingredients into the dry ingredients. Mix until well combined, scraping down the bowl as necessary. Mix until just blended.
Scrape batter into the prepared pan and spread evenly in the pan.
In a small bowl, mix together the vegan spread, brown sugar, 2 Tbsp rice flour, cinnamon, and pecans (if using). Stir until the mixture resembles wet sand.
Spread evenly over the cake, and using a butter knife, gently swirl through the cake, creating the marble-effect. Do not over mix it though.
Bake for 35-40 minutes, or until a toothpick inserted into the center comes out clean.
Remove from oven and allow to cool completely.
When the cake has cooled, prepare the vanilla icing:
In a small bowl, stir together the confectioners sugar, 1/2 tsp vanilla, and 1-2 Tbsp milk. Start with one tablespoon and add more if necessary to get the consistency that you want.
You can use a spoon and drizzle the icing over the cake, or place the icing into a small zipper-seal bag with a small corner cut off, and drizzle it over the cake that way. YUMMO!
Cakes, loaves and breads need to be rotated half-way during baking to ensure even browning. But bulky oven mitts can smear the surface of your cake. To avoid this, use a large pair of tongs to grab the lip of the in and quickly turn it around.