Preheat oven to 350°F. Grease muffin tins with butter.
Add coconut flour, eggs, stevia and melted butter to a bowl and stir to combine. Add a scoop of mixture to each muffin tin and press down to create a bowl covering the bottom and sides.
For filling, add eggs, butter, brown sugar alternative, vanilla and heavy cream to a pot over medium heat and whisk to combine. Keep whisking till butter is all melted and sugar alternative is dissolved. Remove from heat and stir in pecans.
Pour filling into each prepared tart shell.
Bake for 20 minutes, until filling is set and golden. Let them cool 10 minutes before eating.
Notes
I used Splenda Stevia and Swerve Brown Sugar alternative.