Place the washed, halved strawberries in a saucepan with the sugar and lemon juice. Cook over medium heat, stirring occasionally, for 25–30 minutes, until reduced to about a heaping ½ cup of sauce. If the mixture starts sticking to the bottom of the pan, reduce the heat to medium-low and continue cooking. It should be thick and falling off the spatula or spoon into chunks. It will thicken even more as it cools.

Remove from the heat, measure it, and pour into a bowl. Set it aside to cool. You can make the reduction even up to a week ahead and keep in the fridge for when you’re ready to make the muffins.

Beat the cream cheese, powdered sugar, and vanilla in a small bowl with an electric mixer for about 30 to 60 seconds, until completely smooth. Cover with plastic wrap to prevent a skin from forming. Set aside (refrigerate if your kitchen is warm).

Preheat the oven to 425ºF (220ºC).

Grease or line 16 muffin cavities with paper liners. This recipe yields about 20 standard muffins or 8 jumbo muffins.

In a large bowl, whisk together the melted butter, vegetable oil, sour cream, eggs, milk, and vanilla extract until fully combined.

In a separate large bowl, whisk together the flour, baking powder, baking soda, salt, and sugar.

Pour the wet ingredients into the dry ingredients and mix gently with a rubber spatula just until the batter comes together. Do not overmix, or the muffins may turn out dense or dry.

Toss the strawberries with the remaining teaspoon of flour, then gently fold them into the batter.

Spoon about 1½ tablespoons of batter into the bottom of each muffin cavity (about 3 tablespoons if using a jumbo pan).

Add ½ teaspoon of the strawberry reduction over the batter (1 teaspoon for jumbo muffins) and gently swirl with a toothpick.

Top with about 2 teaspoons of muffin batter, followed by 1 heaping teaspoon of cream cheese filling.

Finish by covering with more muffin batter, filling the cavities close to the top.

Add another ½ teaspoon of strawberry reduction on top and gently swirl with the batter, being careful not to disturb the cream cheese layer underneath.

Bake at 425ºF for 7 minutes.

Without opening the oven door, reduce the temperature to 350ºF (175ºC) and continue baking for 12–15 minutes, or until the edges are golden and a toothpick inserted into the muffin (avoiding the cream cheese) comes out clean. Jumbo muffins will require additional baking time.

Let the muffins cool before serving. The tops should be puffed and set—when gently pressed, they should feel firm and not jiggle or leave an indentation.