I'm sorry, it never happen to me that got sticky, even when I cook it without rinsing it and without adding butter. If you need to make them vegetarian and not

I'm sorry, it never happen to me that got sticky, even when I cook it without rinsing it and without adding butter. If you need to make them vegetarian and not vegan, I recommend eggs that are a good binder. If you need to go vegan you can try with a starch binder, for example you can use cornflour mixed with water (I find easy to make a cornflour binder, by cooking some water and adding cornflour slowly with a strainer and mixing well, then cooking it until the consistency is dense enough) when it gets cold the cornflour mix becomes a gelatine ball. You can try also using mashed potatoes, but you need to be careful with water.