In the bowl of a stand mixer with the paddle attachment, pour the egg, lemon juice/milk, lemon zest, and oil in. Turn it on low to lightly combine it. Slowly add in the flour mixture and mix quickly until just combined.
1 egg, Juice of 1 lemon, 4 tablespoons unflavored oil like avocado oil, Zest of 1/2 a lemon
Turn off the mixer and remove the bowl. Gently fold in the raspberries. It's okay if they burst. It might turn your dough a bright raspberry color, that's ok.
1 cup fresh or frozen raspberries
Using a large cookie scoop, divide up the mixture into the muffin cups, filling them about 2/3 full.
Divide up the crumb topping between the 12 muffins, sprinkling them on top and pressing lightly onto the muffin batter if needed.
Bake 20-25 minutes, or until golden brown on top and firm in the center. Transfer to wire cooling rack to cool completely.
Notes
If raspberries are in season, by all means use fresh raspberries! I had to get frozen ones but they still turned out great. I baked my muffins for 20 minutes. They were perfectly moist so if you don't want your muffins to dry out, I suggest you take them out at the 20 minute mark to check with a toothpick and pop them back in if they aren't quite ready yet.