For the browned butter: Add the butter to a medium skillet over medium heat. Cook, swirling the skillet to keep the butter moving around, until it melts and bubbles up, 3 to 4 minutes. When the butter is a medium golden brown, remove the skillet from the heat (it will continue browning in the skillet over the next 30 seconds or so!). Pour the butter and any solids into a bowl and let cool completely, about 30 minutes. Measure out 1/3 cup for the cookies.
For the cookies: To a mixer fitted with the paddle attachment, add the sugar, regular butter, orange zest, vanilla and 1/3 cup browned butter and cream together thoroughly. Add the egg and beat until light and fluffy. Mix in the milk.
Sift together the flour, baking powder and salt in a bowl, then blend it into the creamed mixture. Divide the dough in half, slightly flatten between 2 sheets of waxed paper and refrigerate for 1 hour (or freeze for 20 minutes). The dough needs to be chilled.
Preheat the oven to 350 degrees F. Spray a 24-cup mini muffin tin with cooking spray.
Pinch off pieces of dough and press into the base of the muffin tin cups to make shells. Bake until golden brown, about 12 minutes. Let cool for 5 minutes.
Remove the bases from the tins, spoon 1 teaspoon raspberry jam onto each and serve.