Beat the softened cream cheese with the powdered erythritol until smooth. Swirl in the sugar-free strawberry jam, leaving visible ribbons rather than mixing it fully. Scoop 12 small spoonfuls onto a parchment-lined plate and freeze for 20 minutes until firm.
Preheat your oven to 350F and line a 12-cup muffin tin with parchment liners.
In a large bowl, whisk together the almond flour, erythritol, baking powder, and salt. Add the eggs, melted butter, sour cream, and vanilla extract, and stir until a smooth batter forms. Gently fold in the diced strawberries.
Make the crumble topping by combining the almond flour, cold butter pieces, and erythritol in a small bowl. Use your fingertips to pinch and rub the mixture until it forms coarse, pea-sized crumbs. Set aside.
Spoon about 1 tablespoon of batter into each muffin liner. Place a frozen cheesecake ball in the center of each, then divide the remaining batter on top to cover the filling completely.
Sprinkle the crumble topping evenly over all 12 muffins, pressing it down just slightly so it sticks.
Bake for 22 to 25 minutes, until the tops are golden and the crumble is lightly toasted. A toothpick inserted near the edge should come out clean. Let the muffins cool in the tin for 10 minutes before serving.
