Preheat the oven to 350 degrees F. Grease a 12-cup muffin pan.
Cream the butter, cream cheese, lemon juice and vanilla together until light and fluffy. Add in the eggs, two at a time.
SLOWLY add the dry ingredients. Begin with 1/3 of the bowl, mix and add the second third. Mix again and add the final third. Aim to keep the batter mousse-like. If the batter gets thick and chunky, that's ok also. It makes for a more dense muffin, closer to shortbread, rather than a fluffy cake-like base.
Divide the batter equally into all the muffin wells. Bake for 350 degrees for 30 minutes until golden brown around the edges. They should be firm to touch in the top, once done. Remove from the oven, let cool. After at least 10 minutes, separate the edges with a knife and remove them from the pan. Place on a cooling rack.
Whip the cream and gather the strawberries. Once the muffins are cool, slice in half and stuff with fresh strawberries and a generous amount of whipped cream. Top with extra whipped cream if you have it.
If you use mascarpone cheese, just spread a bit on one half of the muffin and sandwich on top the strawberries.