Preheat oven to 350°F.
In a medium bowl, stir together almonds, crushed graham crackers, melted butter, brown sugar, and salt.
Line the bottom of a 7 to 8” springform pan with a disk of parchment paper. Firmly press crust mixture into bottom of pan using a measuring cup.
Bake crust until set and slightly browned, about 10 minutes. Let cool slightly.
In another medium bowl, beat cream cheese and sugar until smooth, about 1 minute. Add eggs, one at a time, beating at medium speed just until combined. (do not overbeat). Stir in vanilla extract and lemon zest.
Spoon cream cheese mixture on top of crust, smoothing top. Tap cheesecake pan on counter several times to remove any air bubbles.
Add 1 cup water to Instant Pot; place trivet in Instant Pot. Place springform pan inside Instant Pot.
Place top on Instant Pot; twist to seal and lock. Turn Steam Release Valve to “sealing.” Set Instant Pot to cook at High Pressure for 26 minutes.
After cooking is complete, let pressure release naturally (approximately 17 minutes). After that, manually release the pressure by turning the Steam Release Valve to “venting.”
Carefully open Instant Pot lid to avoid dripping condensation on top of cheesecake. Use trivet handles to remove cheesecake from Instant Pot. Let cool, then wrap in plastic wrap, and refrigerate overnight.
Thirty minutes before serving, stir together strawberries, sugar, and Limoncello, if using. Unwrap cheesecake. Remove from pan, and discard parchment paper.
Place cheesecake on a cake plate or pedestal. Top with sour cream. Serve with strawberries. Garnish with lemon zest, if desired.