Preparation:
Combine
strawberries and granulated sugar in a bowl; stir well. Cover and
chill 1 hour. Halve blood oranges crosswise and juice into a bowl.
In a heavy saucepan combine sugar and 1-tablespoon water and cook
over moderately high heat, undisturbed, until sugar begins to melt.
Continue cooking mixture, stirring with a fork, until sugar is melted
and syrup is golden. Remove pan from heat. Carefully add remaining
water down side of pan and stir in blood oranges (caramel will bubble
up and steam). Return pan to heat and simmer sauce, stirring, until
caramel is dissolved, about 5 minutes. Add butter, 1 piece at time,
stirring until incorporated and sauce is smooth. Sauce may be made
2 days ahead and chilled, covered. Reheat sauce over low heat before
serving.