Cinnamon Cake (pareve, vegan option)

This is my new go-to cake. I make it wheat-free (using spelt flour) and nut-free.

Makes one 9 x 13 inch baking pan, or 2-3 loaf pans

2 eggs (or 4 tablespoons flaxseed mixed with 1/2 cup hot water, allowed to cool for 10 min)
1/2 cup oil
1 tsp vanilla extract
1.5 cups sugar
1 cup water + 1 tsp vinegar (I made it with water and vinegar)
3  cups flour (I used whole spelt, you can make it with whole wheat or white wheat, or a mix too)
pinch of salt
3 tsp baking powder

Topping (option 1): 150g walnuts, crushed coarsley
1/2 cup brown sugar
2 tsp ground cinnamon
 OR
Topping (option 2): 
1/3 cup flour
1/2 cup sugar
2 tsp ground cinnamon
1 tablespoon oil
mix together eggs, oil, vanilla, sugar, and water-vinegar mixture. Combine flour with salt and baking powder. Slowly add flour mixture to wet ingredients. Mix well to combine (this is best done with a mixer or a whisk).
Pour HALF the batter into 9 x 13 inch baking pan.
 
Mix topping together, and sprinkle half over batter. Cover with remaining batter. Cover the top of cake with remaining topping mixture.
Bake for about 1 hour at 175 C (check with toothpick to make sure it's done)
Allow to cool before cutting.
Enjoy!