Preheat the oven to 350F (180 C) degrees. Grease and flour a 9x13 inch baking pan.
Add the lemon juice to a liquid measuring cup. Pour the milk into the jug to the 1 1/2 cup mark. Whisk together. Set aside.
In a medium bowl whisk together the flour, cinnamon, baking soda, baking powder and salt and salt.
In a large bowl beat together the butter and sugars until fluffy (about 2-3 minutes).
Add the vanilla into the butter mixture. Then mix the eggs into the butter mixture 1 at a time. Scrape down the sides and bottom of the bowl after each addition.
Cut any bruises off the bananas before mashing. Mix the mashed bananas into the butter mixture. If there are some banana lumps, that's OK.
Mix about 1/3 of the flour mixture into the butter mixture. Then mix in about 1/2 of the milk. Mix in another 1/3 of the flour mixture. Then stir in the rest of the milk. Lastly, mix in the last 1/3 of the flour mixture. Do not overmix. Stop mixing as soon as the batter is an even consistency (lumps of banana are OK - but you don't want lumps of dry ingredients). I typically do the last few additions by hand to avoid overmixing.
Pour the batter into the prepared pan and bake for 40-50 minutes, or until an inserted toothpick comes out clean and the cake is starting to pull away from the edges of the pan. If you aren't 100% sure if the cake is done baking, I recommend baking for a few extra minutes as this cake is unlikely to dry out.