-
1
For the raspberry syrup: Combine the raspberries, lemon juice and 1/3 cup water in a large metal bowl.
-
2
Crush the berries and set the bowl over a pot of simmering water, double-boiler-fashion.
-
3
Cook very gently until the raspberries begin to dissolve, about 15 minutes.
-
4
Pour the mixture into a jelly bag (or a large sieve lined with two layers of cheesecloth) set over a deep bowl.
-
5
Let the mixture drip, gently stirring the pulp now and then but not pressing on it, until it seems that all of the liquid has been expelled, 1 to 2 hours.
-
6
Measure the juice, pour it into a wide-bottomed saucepan and then measure out an equal volume of sugar (for example, for 1 1/2 cups of juice, you'd need 1 /2 cups of sugar).
-
7
Add the sugar to the juice and set the pan over medium-high heat.
-
8
Bring the syrup to a rolling boil (watch to make sure it doesn't boil over), boil for 30 seconds and then remove from the heat.
-
9
Let it settle for a minute, and then carefully skim off the foam.
-
10
Bring to a rolling boil again and then immediately remove from the heat.
-
11
Let it settle, and skim it again.
-
12
Measure out 1/2 cup of the syrup for use in the baked rhubarb and set aside; refrigerate the rest of the syrup for another use.
-
13
For the baked rhubarb: Preheat the oven to 325 degrees F.
-
14
Trim and discard the ends of the rhubarb; cut the stalks into 3/4-inch-thick slices on a deep diagonal, keeping them neatly stacked together.
-
15
Transfer the slices to a 9-by-13-inch baking pan, making rows of cut rhubarb, until you have filled the pan.
-
16
Warm the reserved raspberry syrup in a microwave oven (or a small saucepan) until hot.
-
17
Add the sugar to the warm syrup and stir to dissolve.
-
18
If using the vanilla bean, slice it lengthwise, scrape out the pulp and throw the pulp into the syrup and the pods in with the rhubarb.
-
19
If using vanilla extract, add it to the syrup.
-
20
Pour the raspberry syrup evenly over the rhubarb and bake, uncovered, until the rhubarb is soft but not mushy, 15 to 18 minutes.
-
21
Halfway through baking, remove the pan from the oven, and gently tilt the pan and spoon the syrup over the rhubarb to glaze it.
-
22
Allow the baked rhubarb to cool in the pan, glazing it once more with the syrup as it cools.
-
23
Refrigerate the rhubarb in the pan.
-
24
(The rhubarb will keep in the refrigerator for up to 1 week, and gets firmer and brighter as it sits.)
-
25
Serve over vanilla ice cream.
