Preheat the oven to 400F. Line a Vida by PADERNO Silicone Non-Stick Muffin Pan, 12-cup tin with paper liners. Whisk flour with pecans (if using), baking powder and salt in a large bowl.
In a separate bowl, mash overripe bananas very well (you should have about 1 cup of mash). Stir in the brown sugar, oil, egg and lemon zest. Stir in milk and lemon juice.
Reserve 3 to 4 strawberries for topping, then chop the rest.
Add liquid mixture into flour mixture. Using a rubber spatula, stir until just combined. Add chopped strawberries and stir until just combined.
Immediately spoon or scoop muffin batter into the prepared tin. Top each muffin with some sliced strawberry and banana, tapping each piece gently into the muffin batter.
Bake for 5 min then reduce heat to 350F and bake for another 15 - 20 min, or until muffin tops are golden and a cake tester inserted into the centre of a muffin comes out clean. Let cool in the pan for 10 min then transfer to a rack to cool completely.
Make ahead: Freeze cooled muffins in a zip-lock bag for up to 4 weeks. Thaw at room temperature.