Preheat oven to 350℉. Spray muffins tins with non-stick cooking spray and if using liners spray liners. In a small bowl, combine milk and vinegar, give it a stir, and let sit for 10 minutes.
In a large bowl, combine the melted butter, salt, honey, vanilla, milk and vinegar, greek yogurt, and eggs. Whisk ingredients together well until smooth.
Add the flours, baking powder, and baking soda. Stir to combine. Gently fold in the strawberries, rhubarb, and lemon zest.
Transfer batter to muffin tins, aiming to fill each about 3/4 full. Bake for 25 minutes or until toothpick inserted into muffin comes out clean.
Let muffins cool completely before removing from muffin tin or paper liners.