Drain liquid from the can of garbanzo beans into a mixing bowl. (Set drained garbanzo beans aside and save them for another use.)

Beat bean liquid on high speed for 1 minute. Add cream of tartar and gum and beat on high 1 to 2 minutes.

Add sugar and vanilla and beat on high speed until very stiff.

Add lemon juice, if using, and beat until combined.

Bake unfilled pie shell according to package directions. Let cool.

In a medium saucepan, mix cornstarch with cold water until smooth. Add coconut milk, lemon juice, sugar and turmeric and mix well.

Place mixture on stovetop on medium heat and cook until mixture starts to thicken. Lower heat to simmer.

Stir in vanilla and continue cooking until mixture is very thick.

Pour mixture into cooled baked pie shell. Sprinkle the top with lemon zest, if using.

Let filling cool. Top with egg-free meringue topping by spooning the topping onto pie and swirling it into peaks.

To brown the meringue to look like traditional meringue, place pie under preheated broiler 1 to 2 minutes, watching closely to keep from burning. Rotate pie to brown evenly. Refrigerate 1 hour and serve.