📖 Instructions

1. Before you even think about mixing, preheat your oven to 400°F (200°C). Then, line a 12-cup muffin tin with paper liners or grease it really well. This little step makes a huge difference, trust me. No stuck muffins here!
2. Now for the streusel topping: In a small bowl, whisk together 1/4 cup (30g) all-purpose flour, 2 tablespoons (25g) granulated sugar, and 1/4 teaspoon ground cinnamon. Add 2 tablespoons (28g) cold unsalted butter, cut into small pieces. Use your fingertips or a pastry blender to rub the butter into the dry ingredients until the mixture resembles coarse crumbs. Don't overwork it, okay? Just until it's crumbly. Pop this in the fridge while you make the muffin batter.
3. Time to tackle the fruit! In a medium bowl, gently combine 1 cup (about 150g) diced fresh rhubarb (about 1/4-inch pieces) and 1 cup (about 150g) diced fresh strawberries (also 1/4-inch pieces). Toss them with 1 tablespoon of all-purpose flour. This little trick helps prevent the fruit from sinking to the bottom of your muffins. Nobody wants a bottom-heavy muffin!
4. In a large mixing bowl, whisk together the dry ingredients for the muffins: 1 1/2 cups (180g) all-purpose flour, 1/2 cup (100g) granulated sugar, 2 teaspoons baking powder, and 1/2 teaspoon salt. Make sure everything is well combined. You're aiming for a unified, fluffy dry mix.
5. In a separate, medium bowl, whisk together the wet ingredients: 1 large egg, 1/2 cup (120ml) milk (whole milk gives the best richness!), 1/4 cup (60g) unsalted butter, melted and slightly cooled, and 1 teaspoon pure vanilla extract. Whisk until it's all smooth and creamy.
6. Now, combine the wet and dry. Pour the wet ingredients into the dry ingredients. Mix them with a rubber spatula or wooden spoon *just* until they are combined. The key word here is 'just'! A few lumps are totally fine, even desirable. Overmixing develops gluten too much, leading to tough muffins. We want tender, fluffy ones!
7. Gently fold in your flour-dusted strawberry and rhubarb mixture. Do this carefully so you don't mush the fruit. Again, a few stirs, and you're good. See those vibrant colors? Beautiful.
8. Divide the batter evenly among the 12 prepared muffin cups. Each cup should be about two-thirds full. Don't be shy about getting a good scoop in each one!
9. Remember that streusel from the fridge? Now’s its moment! Sprinkle a generous amount of the streusel topping over the top of each muffin. This is where the magic really starts to happen.
10. Bake for 5 minutes at 400°F (200°C). Then, *without opening the oven door*, reduce the oven temperature to 375°F (190°C) and continue to bake for another 15-18 minutes, or until the muffins are golden brown and a wooden skewer inserted into the center comes out clean. The initial high heat gives them a beautiful dome! Don't worry if your oven timings are a little different, just keep an eye on them.
11. Once baked, remove the muffin tin from the oven and let the muffins cool in the tin for about 5-10 minutes. This helps them set up and makes them easier to remove. Then, transfer them to a wire rack to cool completely. Or, if you're like me, grab one while it's still warm. Pure bliss!