Preheat oven to 325º F. Use parchment paper liners to line a muffin tin. Set muffin pan aside.
Add the eggs, oil, yogurt, vanilla, and lemon zest to a large mixing bowl, and whisk to combine.
In a medium sized mixing bowl, add almond flour, collagen, coconut flour, monk fruit sweetener, baking powder, soda and sea salt. Mix to combine.
Add the dry ingredients into the bowl with the wet ingredients, and stir to combine into a thick batter.
Add blueberries, and fold into the batter.
Scoop the batter into a muffin tin lined with parchment paper liners.
Optionally, make the pecan streusel. Add about 1/2 tablespoon of topping to the top of each muffin, slightly pressing in.
Bake the muffins for 24 minutes, or until the tops have just started to brown and the centers are fully cooked. Increase baking time to 28-30 minutes if using frozen blueberries.
Allow to cool prior to serving.