In food processor, add graham crackers, almonds, cinnamon & sugar; pulse until finely crushed. Add butter; pulse to combine.
Evenly distribute the mixture into the 6 mason jars. Using the back of a tsp press the mixture firmly onto the sides of the jar. You want to make sure the bottom is covered & packed too.
At this time heat 2 - 4 C of water in your microwave. Also, (preheat) turn on your 6 qt crock pot to HIGH.
In a stand mixer add the cream cheese & beat until fluffy. Slowly add in the can of sweetened condensed milk until combined. Add one egg at a time until each combines. Add vanilla extract & lemon zest. Mix until well incorporated.
VERY IMPORTANT STEP: Fill the jars with EQUAL amounts of cheesecake filling. This is so important because you want all the cheesecakes to cook evenly. If you fill one a little more than the others, use a tsp to dip out of one jar & add to another until they are filled as equal as possible. Carefully pour the hot water into the preheated crock pot. Place the jars in the crock pot making sure that none are touching the edges of the ceramic or each other. You're looking for the water to come up 1/2 - 3/4 of the way up on the jars.
Cover crock pot with lid & cook on HIGH for 1 - 1 1/2 hours. You're gong to look for the filling to firm up & not be jiggly in the center. These cooked so quickly because they were cooking in individual, smaller containers.
At this point take the lid off (pick straight up, don't tilt it sideways... you don't want any condensation from lid dropping onto the top of the cheesecakes) & turn the crock pot off. You don't want to try to remove the jars until they cool down at least 15 minutes.
Once the jars have cooled enough to remove, place them on a dish towel to continue cooling. As they cool you will see the filling pull away from the sides of the jars. When they completely cool down (& ONLY when completely cooled) place the lid & rims on the jars & place in the fridge for at least 4 hours. This step gives the flavors a chance to come through...don't skip it! If any are leftover (yea right)...keep those refrigerated until you're ready to eat them.
Serve as is, with berries or even drizzled with caramel or chocolate syrup.