Preheat oven to 350 degrees.
Combine all the dry ingredients (except for the sugar) in a large bowl and whisk to combine.
Add the melted butter to a large (4 cup) measuring cup or bowl. Add the sugar and whisk to combine.
Add the vanilla, lemon juice, and eggs one at a time, whisking to combine between, then add the sour cream and whisk together.
Mix in the sour cream.
Combine the wet ingredients with the dry ingredients, and mix with a spoon.
Add in your fruit or sugar-free chocolate chips, and combine.
Spray your mini muffin tins with cooking spray.
Use your cookie scoop to scoop the batter into muffin tray.
Place muffin tray on baking sheet.
Put muffins into oven on top rack.
Bake for 15 minutes on top rack and then move to middle rack of oven for the final 15 minutes of cooking.
Bake for a total of 30-35 minutes, or until firm.
Remove from oven and let sit for 10-15 minutes in muffin pan, then remove from pan and let them cool on a baking/cooling rack. Muffins will firm up while they cool.
Store muffins in the fridge for 3-4 days, or freeze.