Filling
1 tbsp butter
4 apples, peeled cored and diced
3 tbsp sugar
1 tsp cinnamon
2 tbsp lemon juice
1 tsp flour

Doughnut Muffins
3/4 cups unsalted butter, at room temperature
3/4 cups sugar
2 eggs
1 tsp vanilla
3 cups flour
2 tsp baking powder
1/4 tsp baking soda
1/4 tsp salt
1/2 tsp ground nutmeg
1/2 cup whole milk
2 tbsp yogurt

Cinnamon Sugar Coating
1/2 cup unsalted butter, melted
3 tsps cinnamon
1 cup sugar