Step 1

Position rack in center of oven and preheat to 350°F. Brush softened butter generously all over inside of 12-cup Bundt pan. Sprinkle raw sugar over butter in pan, tilting pan to coat completely.

Step 2

Whisk flour, ground ginger, baking powder, and salt in medium bowl. Using electric mixer, beat 1 cup butter in large bowl until smooth. Add 2 cups sugar; beat on medium-high speed until blended, about 2 minutes. Add eggs 1 at a time, beating well after each addition. Beat in 1 egg yolk and vanilla, stopping to scrape down bowl as needed. Add flour mixture in 3 additions alternately with sour cream in 2 additions, beating on low speed just until blended after each addition. Mix in crystallized ginger. Spread batter in pan, being careful not to dislodge raw sugar.

Step 3

Bake cake until top is light brown and tester inserted near center comes out with a few small crumbs attached, about 55 minutes. Transfer to rack; cool in pan 15 minutes. Gently tap bottom edge of pan on work surface while rotating pan until cake loosens. Place rack atop pan and invert cake onto rack; remove pan. Cool completely.

Step 4

Combine first 4 ingredients in small saucepan. Bring to boil over medium-high heat, stirring until sugar dissolves. Boil until mixture is reduced to scant 1 cup, about 4 minutes. Remove from heat; cool ginger syrup to room temperature (do not strain). DO AHEAD Can be made 2 days ahead. Cover and chill.

Step 5

Place berries in medium bowl. Strain ginger syrup and pour over berries; toss. Cover and chill at least 1 hour. DO AHEAD Can be made 2 hours ahead. Keep chilled.

Step 6

Cut cake into slices and place on plates. Spoon berries with syrup alongside. Sprinkle with mint, if desired, and serve.