1) Preheat oven to 325°F (170°C). Spray 2 (8½x4½-inch) loaf pans with
baking spray with flour. Line pans with parchment paper, letting excess
extend over sides of pan. Spray pans again.
2) In the bowl of a stand mixer fitted with the paddle attachment, beat
butter and cream cheese at medium speed until creamy.
Add sugar and vanilla; beat until fluffy, 3 to 4 minutes, stopping to
scrape sides of bowl. Add eggs, one at a time, beating well after each
addition.
3) In a medium bowl, whisk together flour, salt, and baking powder.
Reduce mixer speed to low.
Gradually add flour mixture to butter mixture alternately with cream,
beginning and ending with flour mixture, beating just until combined
after each addition.
Transfer half of batter to a medium bowl; set aside.
4) In the work bowl of a food processor, pulse strawberries until
smooth, about 1 minute.
5) In a small bowl, whisk together 2 tablespoons water and cornstarch
until smooth.
6) In a medium saucepan, stir together puréed strawberries and sugar
over medium-high heat. Whisk in cornstarch mixture.
Bring to a boil; cook, stirring constantly, until thickened, about 1
minute.
7) Spoon one-third of remaining batter into 1 prepared pan. Spread 0.25
cup Strawberry Sauce onto batter. Repeat layers once; top with remaining
one-third batter.
Using a wooden skewer, gently swirl batter. Repeat procedure with
remaining batter and remaining Strawberry Sauce. Tap pans on counter
twice to release air bubbles.
8) Bake until a wooden pick inserted in center comes out clean, about 1
hour and 10 minutes. Let cool in pans for 10 minutes.
Remove from pans, and let cool completely on wire racks. Serve with
strawberry preserves, if desired.
Notes
1) Substitute strawberry for raspberry or blueberry.