Preheat oven to 375°F. Line a 12-cup muffin tin with liners and set aside.
In a large bowl, combine granulated sugar, eggs, yogurt, vegetable oil, honey, orange zest and vanilla extract. Whisk until combined and smooth. In a separate bowl, combine flour, baking powder and salt. Whisk to combien.
Add flour mixture to the liquid mixture, alternating with the melted butter and stir until just combined. Gently fold in the strawberries and rhubarb. If using frozen fruit, make sure to thaw it first and discard any excess juices or liquid that separate from the fruit.
Fill the prepared muffin cups ¾ full with batter and sprinkle with turbinado sugar. Bake for 25-30 minutes, or until a toothpick inserted in the center of the muffin comes out clean.
Let cool in the muffin tin for 10 minutes, then transfer to a plate for serving, or a cooling rack to cool fully.