Preheat your oven to 350°F (175°C). Line a 12-cup muffin pan or grease it well.
In a small bowl, combine flour, pulsed oats, sugar, lemon zest, and salt. Add butter and vanilla, then use your fingers to mix until soft, clumpy crumbs form. Place in the fridge while preparing the batter.
1/4 cup all-purpose flour, 2 tbsp regular rolled oats, 2 tbsp brown sugar, 2 tbsp unsalted butter, zest of ½ lemon, 1/2 tsp vanilla extract, pinch of salt
In a medium bowl, whisk together flour, baking soda, baking powder, and salt.
1 3/4 cups all-purpose flour, 1 tsp baking soda, 1/2 tsp baking powder, 1/2 tsp fine sea salt
In a large bowl, whisk together butter or oil, honey or maple syrup, yogurt, milk, eggs, vanilla extract, and lemon zest until smooth.
1/4 cup melted butter or avocado oil, 1/3 cup honey or maple syrup, 1/2 cup full-fat plain Greek yogurt, 1/4 cup milk, 2 large eggs, 1 1/2 tsp vanilla extract, zest of 1 large lemon
Add the dry ingredients to the wet and mix until just combined—do not overmix.
Toss Saskatoon berries (fresh or frozen) with 1 tsp flour to prevent sinking. Gently fold them into the batter.
1 cup saskatoon berries
Divide the batter evenly into the 12 muffin cups, filling them nearly to the top.
Sprinkle each muffin with the chilled crumble topping and gently press it down so it sticks.
Bake for 18–22 minutes, or until a toothpick inserted into the center comes out clean or with a few moist crumbs.
Let muffins cool in the pan for 5 minutes, then transfer to a wire rack to cool completely.