Step 1

For pasta dough, mix ingredients and a pinch of salt in an electric mixer fitted with a dough hook on low speed until dough just comes together (3-4 minutes). Turn out onto a work surface and knead by hand until smooth, adding more flour if necessary (4-5 minutes). Divide into 4 even balls, wrap in plastic wrap and refrigerate for 1 hour to rest.

Step 2

For béchamel sauce, melt butter in a saucepan over low heat, add shallot and sauté, stirring occasionally, until translucent (4-5 minutes). Add flour and stir continuously until flour turns sand-coloured (1-2 minutes). Gradually whisk in warm milk until smooth, then cook over very low heat, stirring every minute, until slightly thickened (4-5 minutes). Keep warm.

Step 3

Cook potatoes in a large saucepan of boiling salted water until just tender (2-3 minutes), then drain. Heat olive oil in a frying pan over high heat and sauté cauliflower, parsley and garlic until just tender (2-3 minutes). Add potato and two-thirds of the cauliflower mixture (keep remaining mixture warm) to béchamel sauce and cook over low heat until thickened (4-6 minutes). Stir in 75gm parmesan, season to taste and set aside to cool completely (40 minutes to 1 hour).

Step 4

Working with a piece of pasta dough at a time, roll through the widest setting of a pasta machine, then fold in half and roll through again. Repeat 4-5 times until dough becomes very smooth, then continue rolling the dough through the machine, reducing the settings notch by notch until, 1mm thick. Lightly dust pasta sheets with flour, then cut out as many rounds as possible with a 9cm cutter. Keep them covered with a damp tea towel while you repeat with remaining pasta.

Step 5

Spoon a heaped teaspoonful of potato mixture into the centre of each pasta round and brush around edges with a little water. Fold over to make a half-moon and press around the edges to seal, taking care not to trap any air inside. Join the two corners, twisting and pinching firmly to seal.Set aside on a lightly floured tray while you shape the rest of the tortelloni.

Step 6

Cook tortelloni in a large saucepan of boiling salted water until al dente (5-7 minutes), then drain, reserving at least 80ml pasta water.

Step 7

Meanwhile, heat butter in a large frying pan until nut brown and foaming (3-4 minutes). Add sage, 80ml pasta water, a pinch of salt and remaining parmesan and stir until well combined. Add tortelloni, toss to coat, then serve scattered with remaining cauliflower and baby sage leaves.