Preheat your oven to 425°F (220°C) and line a 12-cup muffin pan with paper liners.

In a medium bowl, combine the flour, sugars, and salt for the streusel topping. Drizzle in the melted unsalted butter, and mix until resembling coarse crumbs. Set aside.

In a large bowl, whisk together the all-purpose flour, baking powder, baking soda, and salt.

Beat the softened unsalted butter and granulated sugar in a large bowl until light and fluffy, about 2 minutes.

Add the eggs one at a time, mixing well after each addition. Stir in the lemon zest, vanilla extract, lemon extract, Greek yogurt, and lemon juice.

Gradually mix the dry ingredients into the wet mixture on low speed until just combined.

In a medium bowl, blend the cream cheese with powdered sugar and a splash of vanilla extract until smooth.

Fill each muffin cup halfway with batter, add a dollop of cream cheese filling, then top with more batter to 2/3-3/4 full. Sprinkle atop streusel.

Bake for 22-25 minutes at 350°F (175°C) until golden brown.

Let muffins cool in the pan for 5-10 minutes before transferring to a wire rack. Prepare the glaze by whisking together powdered sugar and lemon juice until smooth.