Start by making your crust base. Mix 1 cup crushed graham crackers with 1/4 cup melted butter until it looks like wet sand. Press about 1 tablespoon of this mixture firmly into the bottom of each cup in a 12-cup muffin tin lined with paper liners. Pop the tin in your freezer for 10 minutes while you prep the filling—this helps everything stay stable.
Beat your softened cream cheese for about 2 minutes until it's smooth and creamy. Scrape down the sides because lumpy cream cheese ruins the whole vibe of these bites. Add 1/2 cup powdered sugar and 1 tsp vanilla extract, then beat for another minute until combined and fluffy.
In a separate bowl, whip 1 cup heavy cream to stiff peaks using an electric mixer. This takes about 3-4 minutes and honestly it's therapeutic to watch. Gently fold this whipped cream into your cream cheese mixture in two additions—don't overmix or you'll deflate all that air you just created.
Now fold in 1 cup diced fresh strawberries, 1 tsp agar-agar powder, 1 tsp lemon juice, and 1/4 tsp salt. The lemon juice brightens everything and keeps the strawberry flavor from getting too sweet. Mix gently until the strawberries are distributed evenly throughout.
Remove your muffin tin from the freezer and divide the creamy strawberry mixture evenly among all 12 cups. I use a small ice cream scoop which makes this super fast and keeps portions consistent. Smooth the tops with the back of a spoon and make sure each one is pretty level.
Sprinkle 1/2 teaspoon of chopped pistachios on top of each frozen strawberry cheesecake bite. This adds a subtle crunch and looks gorgeous for photos (trust me on this). Pop the entire tin back in the freezer.
Let them freeze for at least 4 hours but overnight is even better. The filling gets creamy-solid and the flavors really develop. Pop them out of the tin and keep them in an airtight container in the freezer until you're ready to serve—they'll last three weeks easy.