Preheat the oven to 425 degrees F.Whisk together the coconut milk, eggs, coconut sugar, vanilla extract, salt, ground cinnamon and lemon zest in a medium bowl until well combined. Set aside.Put the butter in the bottom of a 9x13" pan and put in the preheated oven until it melts.While the butter is melting, peel and slice the apples into ¼ inch thick slices. Once the butter has melted, put the apples in the bottom of the pan. Return the pan to the oven and bake until the apples have started to soften and the butter is starting to brown around the edges, about 10 minutes.Mix the flour and guar gum into the liquids, pour over the apples and bake for another 20 minutes until the pancake is puffy and the top is starting to brown.Remove from the oven and present to your guests quickly as the pancake will deflate as it cools.Serve with your favorite pancake toppings.