If using unblanched almonds, blanch them by pouring boiling water over them and soaking for 2 minutes, then slip off the skins.

Combine almonds and 1 cup room-temperature water in a blender and blend on high for 3 to 4 minutes until creamy and milky.

Add 1 cup boiling water to the almond mixture, stir gently, and let steep at room temperature for 10 to 15 minutes.

Strain the mixture through a fine-mesh strainer into a bowl, pressing gently with a spoon to extract all the liquid.

For a crystal-clear syrup, line the strainer with cheesecloth or a coffee filter and strain the liquid a second time.

Transfer the strained almond liquid to a saucepan, add granulated sugar, orange blossom water, and salt, then warm over medium-low heat for 3 to 5 minutes, stirring until sugar dissolves.

Remove from heat and stir in the almond extract if using.

Allow the syrup to cool to room temperature, then pour into clean glass jars, seal tightly, and refrigerate for up to 3 weeks.