Pour the almond milk into the base of your blender jar. Adding liquid first helps the blades catch the other ingredients instead of spinning uselessly underneath frozen fruit.
Spoon in the almond butter, scraping the spoon clean with a spatula. Add the honey, cinnamon, vanilla extract, and sea salt. Placing the almond butter close to the blades helps it blend evenly instead of clumping.
Drop in the pre-frozen banana, sliced into two or three chunks so the blades can grab it easily. If frozen whole, let it sit at room temperature for 2-3 minutes before slicing.
Secure the lid and blend on high for 45 to 60 seconds, stopping once to scrape down the sides if needed. The smoothie is ready when it looks completely uniform with no visible streaks.
If the smoothie is too thick to blend smoothly, add extra almond milk one tablespoon at a time. For a colder, thicker result, add the ice cubes and blend for another 15-20 seconds.
Taste the smoothie directly from the blender jar before pouring. If you prefer it sweeter, blend in an extra teaspoon of honey rather than stirring it in by hand.
Divide the smoothie evenly between two glasses using a spatula to scrape every bit out of the blender jar. Serve immediately, since the texture is at its thickest and coldest right after blending.