Preheat the oven to 400 degrees F and line a baking sheet with a reusable mat or parchment paper. In a shallow dish, combine coconut milk, ground flax, cinnamon, salt, brown sugar, optional bourbon, and vanilla, stirring to combine. Let sit for a couple of minutes to thicken.

Meanwhile, slice croissants horizontally, almost all the way though. One at a time, place a croissant in the shallow dish and coat with liquid, letting sit for 10 seconds or so. I use a spoon to help cover the liquid on all sides. Place on your prepared baking sheet and repeat with croissant #2. Sprinkle the tops with a bit more brown sugar if desired. 

Bake for 10-13 minutes, until dark brown and crispy. Some sugar may burn as it slides off onto the parchment, so keep an eye on this (it's not a big deal though). 

Spoon yogurt or cream inside of the croissants (like a sandwich) and fill with sliced berries. Garnish with a sprig of mint and serve with warmed maple syrup.