Oatmeal Muffins

INGREDIENTS

• Crumble topping:
• scant 3/4 cup / 3 oz / 85 g whole wheat pastry flour
• 1/2 cup / 1.5 oz / 45 g rolled oats
• 1/2 cup / 2.5 oz / 70 g natural cane or brown sugar
• scant 1/2 teaspoon fine grain sea salt
• 1/3 cup / 2.5 oz / 70 g unsalted butter, melted
• Muffin batter:
• 1 cup / 3.5 oz / 100 g rolled oats
• 3/4 cup / 3.5 oz / 100 g unbleached all purpose flour
• 3/4 cup / 3.5 oz / 100 g whole wheat pastry flour
• 1/2 teaspoon baking soda
• 7/8 cup / 7 oz / 200 g unsalted butter, plus more for greasing pan
• 1 1/2 cups / 12 oz / 350 ml plain yogurt
• 2 large eggs, whisked