Prepare the custard in advance so it is cold & ready to pipe once the eclairs are done baking & fully cooled.
Combine the sugar with the cornstarch & agar powder then add that to the plant milk in a large sauce pot
Bring everything to a full rolling boil over medium to high heat whisking constantly to avoid scorching
Once it comes to a full boil remove from the heat add the vegan butter & the vanilla extract, whisk smooth
Transfer the hot custard to a heatproof vessel to cool. Refrigerate until ready to fill
Preheat the oven to 425°F & make the Pate Choux Dough
Combine the plant milk with the vegan butter, sugar & pinch of salt in a medium sauce pot~ bring to a boil
In a 2 cup measuring glass combine the aquafaba, egg replacer, water & apple cider vinegar whisk smooth it will bubble up if using Bob's Red Mill Egg Replacer
In a medium bowl combine the all purpose flour & chick pea flour, baking powder, methocel & xantham gum
Once the plant milk mixture comes to a full boil, add the dry ingredients & stir with a wooden spoon. The mixture may bubble up slightly so be sure that you have a large enough pot to accommodate everything.
Transfer the entire mixture to a mixing bowl with a paddle attachment (a hand beater will be fine here)
On low speed add about ¼ cup at a time of the aquafaba/water mixture allowing the dough to absorb everything before the next addition
Repeat until all the liquid is used & the dough looks like thick mashed potatoes.
Transfer this choux paste to a pastry bag fitted with a round tube or I just use a coupler & no tip inserted and pipe 3" long logs (or rounds for cream puffs) onto a silicone mat
Bake in a preheated 425°F convection oven setting for 15 minutes then turn down to 400°F convection setting 24 more minutes
Turn the oven off and let them cool inside for 5 minutes
Remove from the oven and cool completely
Fill with pastry cream
Dip the tops of the filled eclairs in melted chocolate & drizzle with white chocolate
Add a rosette of whipped cream to the cream puffs *optional