Preheat your oven to 375°F (190°C). Line a standard 12-cup muffin tin with paper liners. This prevents sticking and makes cleanup easy. Allow the oven to fully preheat for about 10 minutes.

In a medium bowl, whisk together 2 cups all-purpose flour, 1 teaspoon baking powder, 1/2 teaspoon baking soda, and 1/4 teaspoon salt. Mix for about 30 seconds until evenly combined. Checkpoint: You are ready to move on when the dry ingredients are evenly distributed with no lumps.

In a large bowl, add 1/2 cup softened unsalted butter and 3/4 cup granulated sugar. Using an electric mixer on medium-high speed, beat for 2–3 minutes until the mixture is light, fluffy, and pale. Scrape down the sides of the bowl halfway through. Checkpoint: The mixture should look like fluffy frosting when done.

Add 2 large eggs to the butter mixture, one at a time, beating on medium speed for about 20 seconds after each egg. The mixture should look smooth after each addition. This helps emulsify the batter.

Add 1/2 cup plain Greek yogurt, 1/4 cup fresh lemon juice, 2 tablespoons lemon zest, and 1 teaspoon vanilla extract to the wet mixture. Beat on medium speed for about 1 minute until well combined. The mixture will look slightly curdled but will come together after mixing with the dry ingredients.

Pour the dry ingredients into the wet ingredients. Using a rubber spatula or wooden spoon, gently fold together for about 30 seconds. Stop folding as soon as you see no white flour streaks. Do NOT use an electric mixer here. Overmixing develops gluten and makes tough muffins. Checkpoint: The batter should look lumpy and thick, not smooth.

In a small bowl, toss 1 1/4 cups fresh raspberries with 1 tablespoon all-purpose flour. Gently fold the floured raspberries into the batter using just 2–3 folds. The flour coating prevents the raspberries from sinking and bleeding into the batter. Checkpoint: You should see small raspberry pieces distributed throughout the batter.

For the streusel topping: In a small bowl, mix 1/2 cup all-purpose flour, 1/4 cup granulated sugar, 1/4 cup packed light brown sugar, 1/4 teaspoon salt, and 1 tablespoon lemon zest. Stir for about 20 seconds to combine.

Add 3 tablespoons cold unsalted butter, cubed, to the streusel mixture. Using your fingertips, rub the butter into the flour mixture for about 1 minute until it looks like coarse breadcrumbs (pieces should range from pea-sized to sand-grain sized). Do not overmix. Checkpoint: The mixture should hold together slightly when squeezed but still look crumbly.

Stir 1/2 cup sliced almonds into the streusel mixture. Gently toss for about 10 seconds to distribute. Set aside.

Spoon the batter into the prepared muffin cups, filling each about two-thirds full. Use an ice cream scoop or spoon to divide the batter evenly. This ensures even-sized, evenly-baked muffins.

Sprinkle the streusel mixture generously and evenly over each muffin, using about 1 1/2 tablespoons per muffin. Press gently so the topping adheres slightly to the batter.

Place the muffin tin on the center oven rack. Bake at 375°F for 20–25 minutes. Begin checking at 20 minutes.

The muffins are done when: (1) a toothpick inserted into the center of a muffin comes out with just a few moist crumbs (not wet batter), (2) the streusel topping is golden brown, and (3) the muffin edges pull slightly away from the tin. If tops are browning too quickly but centers feel soft, reduce oven temperature to 350°F and bake 3–5 minutes longer.

Remove the muffin tin from the oven and place on a wire cooling rack. Allow muffins to cool in the tin for 5 minutes. This helps them set and makes them easier to remove.

Gently peel away or push down the paper liners from the sides of each muffin and transfer to a wire cooling rack. Cool for at least 15 minutes before serving. This allows the crumb to set fully. Checkpoint: Muffins should feel firm but still warm to the touch.

If serving warm, you can enjoy muffins after 15–20 minutes of cooling. For best flavor and texture, allow to cool to room temperature (about 30 minutes total).