To Prepare the Blueberry Jam Filling

1. Combine the jam, cardamom, and vanilla together in a small bowl. Set this mixture aside.

To Prepare the Muffins

1. Get your muffin tins ready. Spray them with baking spray or place paper liners inside each cup.
2. Preheat your oven to 400 degrees Fahrenheit (200 degrees Celsius).
3. In a large mixing bowl, whisk together the dry ingredients. Set this bowl aside for now.
4. In a separate medium bowl or a large measuring cup with a spout, mix the wet ingredients.
5. Pour the wet ingredients into the large bowl with the dry ingredients. Gently mix until they are just combined. Using a large fork first helps, then use a soft rubber spatula to scrape the sides and bottom to finish. Remember, a few lumps in the batter are perfectly fine and even preferred for tender muffins.
6. Spoon batter into each prepared muffin cup, filling them about halfway.
7. Add one teaspoon of the prepared jam filling into the center of the batter in each muffin cup.
8. Spoon the remaining muffin batter over the jam filling in each cup, filling them almost completely.
9. Place one more teaspoon of jam on top of the batter in each cup. Use a chopstick or a small skewer to swirl the jam down into the batter, moving from the top through the center and side to side slightly.
10. You can bake the muffins right away, or for a slightly higher rise, let them sit at room temperature for about 20 minutes before baking. Use this time to tidy up your kitchen workspace.
11. Place the filled muffin tins into the preheated oven. Bake for 15 to 18 minutes. They are done when they are puffed up, golden brown, and look set in the center. This is a good time to prepare your glaze.
12. Carefully remove the hot muffins from the oven. Let them cool in the tin for a few minutes before transferring them to a parchment-lined surface (like a cookie sheet, cutting board, or large platter) to cool completely before you apply the glaze.

To Prepare the Glaze

1. Put all of the glaze ingredients into a small bowl. Begin adding milk, one tablespoon at a time. Mix until you have a smooth glaze that is pourable but still thick enough to coat the muffins without running off completely. If the glaze is too thin, add a little more confectioner’s sugar. If it is too thick, add a few drops more milk.

To Glaze Muffins

1. Once the muffins have cooled entirely to room temperature, you can glaze them. Spread or pour the glaze over the muffin tops in any way you prefer. A simple drizzle looks lovely, or you could dip the top of each muffin into the glaze.