Pumpkin and Feta Muffins

INGREDIENTS

• 1 tablespoon unsalted butter
• 2 tablespoons olive oil
• 2 cups / 9 oz / 255g cubed pumpkin or butternut squash, 1/2-inch cubes
• salt and pepper to taste
• 1 large handful of baby spinach, chopped
• 2 tablespoons chopped parsley or cilantro
• 3 tablespoons sunflower seeds kernels
• 3/4 cup / 1 oz / 30g freshly grated Parmesan
• 100g / 3.5 oz / 1/2 cup cubed feta
• 2 teaspoons whole-grain mustard
• 2 large eggs, lightly beaten
• 3/4 cup / 180 ml milk
• 2 cups flour (see headnote!)
• 4 teaspoons aluminum free baking powder
• 1 teaspoon fine-grain sea salt