Chai-Spiced Crumb Coffee Cake

Preheat oven to 350F. Line a 9-inch square baking pan with parchment paper or lightly greased aluminum foil.

Start by making a crumb topping. In a small saucepan, melt half a cup of the butter. Remove from heat and set aside. In a medium bowl, combine 1/3 cup of the sugar, brown sugar, cinnamon, ginger, cardamom, allspice, 1/2 teaspoon of the salt, and 1 1/2 cups of the flour. Mix well. Gradually stir in the melted butter, using a large fork or spatula. When all the butter has been incorporated and the mixture looks like wet sand, squeeze small clumps together to make large crumbs ranging in size from that of a pea to that of a grape. Set the topping aside.

In a medium bowl, whisk together remaining flour, baking powder, baking soda and the rest of the salt.

In a large bowl, cream the rest of the butter and sugar together until light. Beat in eggs, one at a time, followed by vanilla extract. With a mixer set on a low speed (or by hand), alternately add in flour mixture and sour cream.. When no streaks of flour remain, pour into prepared pan. Top evenly with crumb mixture.

Bake at 350˚F for about 45 minutes, or until a toothpick inserted into the center comes out clean.

Cool on a wire rack before slicing.