Stir together the cubed croissants, almonds, and almond paste in a medium bowl.
In a separate bowl, whisk together the milk, brown sugar, egg, cinnamon, almond extract, and salt.
Pour the milk mixture over the bread mixture, and stir until all the bread has been coated.
Divide the mixture between the prepared ramekins. Cover and refrigerate for an hour or up to overnight.
Place the chilled bread puddings on a lined, rimmed baking sheet. If using, sprinkle the top of each with more almonds and a heavy pinch of cinnamon-sugar.
Preheat the oven to 350°F (175°C).
Bake 30-35 minutes, or until the tops are browned and a thin knife inserted into the center comes out clean. Cool briefly and serve warm with any desired toppings.
Notes
*You may want to adjust the cinnamon to your tastes and depending on whether you're using cinnamon-sugar on top.
Store in the airtight container in the refrigerator up to 5 days.