Combine ½ cup (75g) blueberries, lemon juice, 1 tablespoon sugar, and 1 tablespoon water in a small saucepan over medium heat. Stir to dissolve sugar, about 4 to 5 minutes. Removed and set aside to cool.
In a large bowl, combine heavy whipping cream and 1 teaspoon sugar. Whip with electric mixer until soft peaks form. Set aside.
In another bowl, whip cream cheese until smooth. Fold in half of the whipped cream.
Grind toasted sliced almonds until fine.
Place tart shells on a large plate. Fill each shell with a teaspoon of ground almonds.
Top with a tablespoon of cream cheese mixture. Then, divide remaining blueberries equally among the 4 tart shells.
Top each tart with whipped cream and drizzle with blueberry sauce. Sprinkle with remaining ground almonds.