Happy birthday! I assume you already went out, but for the future: Cookhouse in Bolton Hill often features at least one plant-based ~fancy~ dining option. The restaurant itself is small and would be a great birthday spot! Good drinks if you drink, too. Current plant based (and gluten free!) option is risotto (arborio rice, wild mushrooms, wine, mushroom stock, plant-based parmesan).

My best buddy is vegetarian. When they wanna take me out for dinner they always have me decide on the location so I try to look at the menus and straight up ask "which item sounds best" and go from there, hahaha.