Preheat the oven to 400 degrees. Line a muffin pan with 12muffin liners. Set this aside.
Mix together the streusel ingredients and set them aside as well.
Mix the flour, baking powder, baking soda, and salt together in a small bowl and set aside.
In another medium-sized bowl, mix the melted butter, oil, and sugar. After they are well blended, add the Greek yogurt, eggs, lemon juice, lemon zest, milk, and vanilla.
Combine the wet ingredients with the dry ingredients, making sure to only mix until it is combined together. Do not overmix. Fold in the strawberries.
Scoop into the muffin pans. This batter will fill them up to the top.
Top with the streusel batter and place in the oven.
If you are using whole wheat flour- which I recommend, these muffins will take about 15-18 minutes to bake. The whole wheat flour absorbs more moisture, so don't overbake these!
If you are using only all-purpose flour, the baking time will be 17-20 minutes.
I check by gently pressing the top middle of each muffin. It should feel JUST SLIGHTLY underbaked. Not too much, but just a little
Remove the pan from the oven and allow them to cool for about 5 minutes.
Gently take the muffins from the pan and set them on a cooling rack.