Add liquid first. Pour almond milk into the blender.
Add peanut butter and yogurt. Add peanut butter and Greek yogurt. These need to blend with the liquid before frozen ingredients are added.
Add protein powder and cocoa. Add chocolate protein powder and unsweetened cocoa powder. The cocoa intensifies the chocolate flavor beyond what protein powder alone provides.
Add frozen banana and other ingredients. Add frozen banana, ground flaxseed, honey if using, vanilla extract, and a pinch of salt. The salt enhances chocolate and peanut butter flavors.
Add ice. Top with ice cubes for a thick, cold consistency.
Blend thoroughly. Start on low and gradually increase to high. Blend for 60-90 seconds until completely smooth with no peanut butter chunks.
Check thickness. This smoothie should be very thick -- almost spoon-able. If it's too thick to drink, add almond milk 2 tablespoons at a time.
Serve immediately. Pour into a large glass. This smoothie is rich enough that sipping slowly is natural.