Simmer the blueberry layer. Add blueberries, sweetener, lemon zest, lemon juice, vanilla, and a pinch of salt to a small saucepan. Cook over medium heat, stirring occasionally, until berries burst and the mix thickens slightly, about 6–8 minutes.
Taste and adjust sweetness. Let it cool to room temperature.
Toast the crumb. In a skillet over medium-low heat, combine almond flour, chopped nuts, sweetener, cinnamon, and salt. Stir for 3–5 minutes until lightly golden and fragrant.
Remove from heat and stir in melted butter. Let it cool so it crisps up.
Whip the cream. In a cold bowl, whip the heavy cream to soft peaks. Set aside.
Beat the cream cheese. In another bowl, beat softened cream cheese with sweetener, vanilla, lemon juice, and a pinch of salt until smooth and fluffy, 1–2 minutes.
Fold together. Gently fold the whipped cream into the cream cheese mixture in two additions.
Stop when it looks smooth and airy. Avoid overmixing.
Assemble the layers. Spoon a tablespoon or two of crumb into the bottom of each glass. Add a layer of cheesecake mousse, then a spoonful of blueberry compote.
Repeat layers, ending with blueberries on top.
Chill and garnish. Refrigerate for at least 30 minutes to set. Before serving, top with fresh blueberries and a little lemon zest if you like.