Preheat the oven to 350 °F, and line a 9" x 13" cake pan with parchment paper.
Add the chia seeds to 4 tablespoons of water in a small bowl.
Set aside for now – it will gel as you prepare the rest.
In a large bowl, combine the flour, lemon zest, finely ground almonds, baking powder and salt. Whisk to sift together, blending well.
In a second bowl, beat the oil with the lemon juice, oat milk and vanilla extract.
Beat the sugar into the wet ingredients. Add the gelled chia seeds last.
Add the dry ingredients to the wet in three batches, mixing until well blended, but not over-beaten.
Pour into the prepared cake pan.
Drop the cherries into the batter, letting them fall into the cake all over the pan.
Bake for 35 to 40 minutes, until a sharp knife inserted into the center comes out clean.